How to Hike Trail 100 in Phoenix

Trail 100 in Phoenix is not a single, officially designated hiking path like the Appalachian Trail or the Pacific Crest Trail. Rather, it is a legendary, self-guided long-distance route that traverses the rugged desert landscapes surrounding the Phoenix metropolitan area, connecting a network of trails, fire roads, and natural corridors. Often referred to by local hikers as “The Phoenix 100,” this unofficial 100-mile loop is a test of endurance, navigation, and desert resilience. It weaves through the McDowell Mountains, South Mountain Park, the White Tank Mountains, and the Estrella Mountains — offering unparalleled views of Sonoran Desert ecosystems, ancient petroglyphs, and sweeping vistas of the Valley of the Sun.

While not marked on standard maps or maintained by a single park authority, Trail 100 has gained cult status among serious hikers, ultrarunners, and outdoor enthusiasts seeking to challenge themselves beyond typical day hikes. Completing Trail 100 is not just about physical achievement — it’s a deep immersion into the geography, history, and ecology of one of America’s most unique desert environments. For those who undertake it, the journey becomes a rite of passage, demanding preparation, respect for nature, and a keen awareness of desert hazards.

This guide is your comprehensive, step-by-step resource to safely and successfully hike Trail 100 in Phoenix. Whether you’re a seasoned backpacker or an ambitious day-hiker looking to tackle a multi-day adventure, this tutorial will equip you with the knowledge, tools, and mindset needed to navigate this extraordinary route. We’ll break down the logistics, highlight best practices, recommend essential gear, share real-world experiences, and answer the most common questions. By the end, you’ll understand not just how to hike Trail 100 — but how to honor it.

Step-by-Step Guide

Understand the Route and Its Segments

Trail 100 is not a single trail with signs or blazes. It’s a curated combination of existing trails and fire roads, stitched together by experienced desert travelers. The most commonly accepted route spans approximately 100 miles and forms a rough loop around the greater Phoenix area. It is typically broken into six main segments:

• Segment 1: South Mountain Park to the Estrella Mountains — Begins at the Dobbins Lookout Trailhead and follows the South Mountain Preserve trail system, exiting via the Black Mountain Trail to connect to the Estrella Mountain Regional Park.
• Segment 2: Estrella Mountains to the White Tank Mountains — Travels north along the Gila River floodplain, crossing remote desert flats and connecting via the Estrella Trail to the White Tank Mountain Trailhead.
• Segment 3: White Tank Mountains to the McDowell Mountains — Ascends through rugged washes and climbs into the McDowell Sonoran Preserve, using the Gateway Loop and Tom’s Thumb Trail as key connectors.
• Segment 4: McDowell Mountains to the Phoenix Mountains Preserve — Descends via the Piestewa Peak access road and transitions to the North Mountain trails, crossing the Salt River bed.
• Segment 5: Phoenix Mountains Preserve to South Mountain Park (via the Papago Buttes) — Uses the Desert Botanical Garden trail connections and the Papago Park trail system to link back toward the southern reaches of South Mountain.
• Segment 6: South Mountain Park Loop Completion — Returns to the starting point via the High Point Trail and the Mescal Trail, completing the loop.

Each segment averages 15–20 miles and can be completed in a single day by experienced hikers, though most complete the full loop over 5–7 days. GPS coordinates and trail junctions are critical — many of these connections are not signed. Always carry offline maps and a backup navigation tool.

Plan Your Timing and Season

The Phoenix area experiences extreme temperatures, especially from May through September, when daytime highs regularly exceed 105°F (40°C). Hiking Trail 100 during these months is not recommended unless you are a highly experienced desert survivalist with specialized equipment.

The optimal time to hike Trail 100 is between late October and early April. During this window, daytime temperatures range from 65°F to 80°F (18°C–27°C), and nighttime lows remain above freezing. Early mornings are ideal for starting hikes — begin at sunrise to avoid the midday heat and to take advantage of the soft, golden light that illuminates the desert landscape.

Winter months (December–February) offer the coolest conditions but can bring occasional cold fronts. Pack layers, including a windproof jacket, and be prepared for temperatures to drop below 40°F (4°C) at higher elevations, especially in the McDowell Mountains.

Obtain Necessary Permits and Permissions

Trail 100 passes through multiple jurisdictions: Maricopa County Parks, Phoenix Parks and Recreation, and the Tonto National Forest. While no single permit is required to complete the entire route, you must comply with the rules of each area you enter.

South Mountain Park and Estrella Mountain Regional Park require no permit for day hiking, but overnight camping is restricted to designated areas. In White Tank Mountains Regional Park, camping permits are required for backcountry sites and must be reserved in advance through the Maricopa County Parks website. The McDowell Sonoran Preserve requires a free day-use permit, which can be obtained online at McDowellSonoran.org.

Always check for seasonal closures due to wildlife protection, fire risk, or maintenance. Some trails in the Papago Park area close during nesting season for raptors. Respect all posted signs and avoid off-trail travel in protected ecological zones.

Prepare Your Gear and Supplies

Trail 100 demands gear that balances weight, durability, and desert-specific functionality. Below is a recommended packing list:

• Backpack: 30–40L capacity with a hydration-compatible design and hip belt support.
• Hydration: Minimum 3 liters of water capacity per person. Use a hydration bladder (e.g., CamelBak) plus two 1L hard-sided bottles. Carry a water filter or purification tablets as backup.
• Footwear: Sturdy, broken-in hiking boots with aggressive tread. Avoid trail runners unless you have exceptional ankle support and experience on rocky terrain.
• Clothing: Moisture-wicking base layers, UV-protective long sleeves, wide-brimmed hat, neck gaiter, and sunglasses. Avoid cotton — it retains moisture and increases risk of hypothermia at night.
• Navigation: Garmin inReach Mini 2 or similar satellite communicator with offline maps. Download all segments on Gaia GPS or AllTrails Pro. Carry a physical topographic map and compass as backup.
• Emergency Kit: Include whistle, emergency blanket, first aid supplies (blister care, antiseptic, pain relievers), fire starter, multi-tool, and a headlamp with extra batteries.
• Food: High-calorie, non-perishable snacks: nuts, dried fruit, energy bars, jerky, and electrolyte packets. Plan for 2,500–3,500 calories per day depending on exertion.
• Camping Gear (if overnighting): Lightweight tent, sleeping bag rated for 40°F, sleeping pad, portable stove, and bear-resistant food container (even though bears are rare, rodents are abundant).

Never underestimate the desert’s ability to dehydrate you. Even in winter, sweat loss can be extreme due to low humidity. Drink water consistently — don’t wait until you’re thirsty.

Start at the Right Trailhead

The most common starting point is Dobbins Lookout in South Mountain Park, due to its accessibility, parking availability, and elevation gain that provides early panoramic views. Parking is free but fills quickly on weekends — arrive before 6:00 AM.

Alternative starting points include the Estrella Mountain Regional Park Visitor Center (for those approaching from the west) or the McDowell Sonoran Preserve’s Gateway Trailhead (for those starting from the north). Choose your starting point based on your logistics, vehicle access, and desired direction of travel.

Before you begin, take a photo of your vehicle’s license plate and the trailhead sign. Share your itinerary with a trusted contact, including your planned route, checkpoints, and expected return time. Cell service is unreliable along most of the route — rely on satellite communication.

Navigation: How to Stay on Course

Trail 100 has no official signage. Missteps are common and can lead to dangerous detours. Here’s how to stay on track:

1. Download the official Trail 100 GPX file from the Arizona Hiking Club’s website or the Trail 100 Project (trail100phx.org). Transfer it to your GPS device.
2. Mark every junction on your map with a waypoint. Key intersections include: Black Mountain Junction, Estrella Wash Connector, and the McDowell Loop Intersection.
3. Use natural landmarks: the distinctive shape of Tom’s Thumb rock formation, the red cliffs of the White Tank Mountains, and the spire of Piestewa Peak.
4. Check your GPS every 15–20 minutes. If you’re off by more than 200 feet, stop and reorient using your compass and topographic map.
5. Never rely on cell apps like Google Maps. They lack trail detail and will fail without service.

Many hikers report getting disoriented near the Salt River crossing — the terrain flattens and trail markers disappear. Use the GPS to locate the nearest vehicle track and follow it until you reconnect with the designated trail.

Manage Daily Mileage and Rest

Most hikers cover 15–20 miles per day on Trail 100. Pushing beyond 25 miles in a single day increases risk of heat illness and injury. Plan your daily segments to end at established rest points:

• Day 1: Dobbins Lookout to the Estrella Mountain Visitor Center (18 miles)
• Day 2: Estrella to the White Tank Mountain Trailhead (17 miles)
• Day 3: White Tank to the McDowell Sonoran Preserve (20 miles)
• Day 4: McDowell to the North Mountain Trailhead (16 miles)
• Day 5: North Mountain to Papago Park (15 miles)
• Day 6: Papago to Dobbins Lookout (14 miles)

Rest for 10–15 minutes every 90 minutes. Sit in the shade, hydrate, and stretch your calves and hamstrings. Use this time to check your feet for blisters — early intervention prevents major issues.

Handle Desert Emergencies

The desert is beautiful but unforgiving. Know how to respond to common emergencies:

• Heat Exhaustion: Symptoms include heavy sweating, dizziness, nausea, and rapid pulse. Move to shade, loosen clothing, and sip cool water. Apply wet cloths to neck and wrists.
• Heat Stroke: A medical emergency. Signs: hot, dry skin, confusion, loss of consciousness. Call for help immediately via satellite device. Cool the person with water and shade while waiting.
• Dehydration: Dark urine, dry mouth, fatigue. Prevent by drinking 1 liter per hour during exertion. Use electrolyte supplements.
• Snake Bite: Most snakes in the area are non-venomous. If bitten by a rattlesnake, remain calm, remove constricting items, keep the bite below heart level, and seek help immediately. Do NOT cut, suck, or apply ice.
• Getting Lost: Stop. Assess. Do not wander. Use your GPS to determine your location. If you cannot reorient, stay put and activate your emergency beacon.

Always carry a personal locator beacon (PLB) or satellite messenger. A Garmin inReach or SPOT device can send your coordinates to emergency responders even in remote zones.

Best Practices

Leave No Trace Principles

Trail 100 runs through ecologically sensitive desert terrain. The Sonoran Desert is one of the most biodiverse deserts on Earth, home to saguaros, Gila monsters, and rare desert tortoises. Follow these Leave No Trace guidelines:

• Plan Ahead and Prepare: Know regulations, weather, and terrain. Bring the right gear to minimize impact.
• Travel and Camp on Durable Surfaces: Stick to established trails and campsites. Avoid walking on cryptobiotic soil — the fragile crust that prevents erosion and supports plant life.
• Dispose of Waste Properly: Pack out all trash, including food scraps and toilet paper. Use a portable toilet or dig a cathole 6–8 inches deep at least 200 feet from water, trails, and campsites.
• Leave What You Find: Do not pick cactus flowers, collect petroglyph rubbings, or remove rocks or artifacts. These are protected by federal law.
• Minimize Campfire Impact: Fires are prohibited in most areas. Use a camp stove instead.
• Respect Wildlife: Observe from a distance. Never feed animals. Store food securely to avoid attracting rodents and coyotes.
• Be Considerate of Other Visitors: Yield to hikers going uphill. Keep noise levels low. Share the trail.

Hydration and Nutrition Strategy

Hydration is the single most critical factor for success on Trail 100. The desert air can evaporate sweat faster than you can replace it. Here’s a proven hydration protocol:

• Start each day with 1 liter of water and 1 electrolyte tablet before sunrise.
• Carry 3–4 liters total per day. Refill at designated water stations in South Mountain and McDowell Sonoran Preserve — but never assume water is available.
• Drink 1 cup (250ml) every 20 minutes during hiking, even if you’re not thirsty.
• Use electrolyte powders (like Nuun or LMNT) to maintain sodium balance. Low sodium can cause hyponatremia — a dangerous condition from overhydration without electrolytes.
• Eat small, frequent snacks: 100–150 calories every hour. Prioritize fats and proteins for sustained energy over simple carbs.
• After hiking, consume a meal with a 3:1 ratio of carbohydrates to protein within 30 minutes to aid recovery.

Physical and Mental Preparation

Trail 100 is not a casual hike. It requires months of preparation.

Physical Training:

• Begin 3–4 months before your hike with weekly long hikes (10+ miles) on uneven terrain.
• Include elevation gain — find hills or stairs to simulate desert ascents.
• Train with your full pack (30+ lbs) at least twice a week.
• Strengthen your core, glutes, and calves with squats, lunges, and step-ups.
• Practice walking on sand, loose rock, and steep inclines — these are common on Trail 100.

Mental Preparation:

• Visualize challenging moments — heat, isolation, fatigue — and rehearse your response.
• Practice solitude. Take solo day hikes to build comfort with being alone in nature.
• Set small daily goals. Celebrate each milestone — reaching a viewpoint, completing a segment.
• Accept that things will go wrong. A blister, a wrong turn, a sudden windstorm. Flexibility and calm are your greatest tools.

Weather and Environmental Awareness

Phoenix weather is unpredictable. Even in winter, sudden thunderstorms can cause flash floods in washes — the most dangerous hazard on Trail 100.

• Check the National Weather Service forecast daily. Look for “hazardous weather outlooks” for Maricopa County.
• Avoid hiking in washes if rain is predicted anywhere within 50 miles. A storm in the McDowells can flood the Salt River 3 hours later.
• Watch for darkening skies, distant thunder, or sudden wind shifts. If you hear a rumbling like a freight train, move to high ground immediately.
• Wind can drop temperatures rapidly after sunset. Always carry a windbreaker.
• UV radiation is intense. Even on cloudy days, sunburn can occur in under 20 minutes. Use SPF 50+ sunscreen and reapply every 2 hours.

Trail Etiquette and Community

Trail 100 is shared by hikers, mountain bikers, and equestrians. Respect the hierarchy: hikers yield to horses, bikers yield to hikers. Announce your presence politely when approaching from behind.

Join the Trail 100 community on Reddit (r/Trail100Phoenix) or Facebook groups. Many hikers share real-time updates on trail conditions, water availability, and recent wildlife sightings. This informal network is invaluable.

Never litter, cut switchbacks, or blaze new trails. The desert heals slowly — your footsteps can leave a mark for decades.

Tools and Resources

Recommended GPS and Mapping Tools

• Garmin inReach Mini 2: Two-way satellite messaging with built-in GPS and SOS. Essential for safety.
• Gaia GPS App: Download topographic maps for Arizona. Use the “Arizona Trails” layer for Trail 100 segments.
• AllTrails Pro: User-submitted trail logs with photos and recent conditions. Filter by “long-distance” and “multi-day.”
• CalTopo: Free web-based mapping tool. Create custom route overlays and print paper backups.

Books and Guides

• Arizona’s Best Day Hikes by Robert Adamson — covers key segments of Trail 100.
• The Sonoran Desert: A Natural History by David Yetman — essential for understanding the ecosystem you’re traversing.
• Desert Hiking: Survival and Skills by John Muir Laws — practical advice on navigation, water sourcing, and wildlife.

Official Websites and Permits

• South Mountain Park & Preserve — trail maps and alerts
• Maricopa County Parks — permits for Estrella and White Tank
• McDowell Sonoran Preserve — day-use permits and trail conditions
• Arizona Game and Fish Department — wildlife safety and seasonal closures

Community and Volunteer Resources

• Arizona Hiking Club: Organizes monthly group hikes and publishes the Trail 100 GPX file.
• Friends of South Mountain: Volunteer trail maintenance opportunities — great way to give back.
• Trail 100 Project (trail100phx.org): Crowdsourced data, user logs, and interactive map.

Mobile Apps for Real-Time Updates

• Windy: Real-time wind and temperature forecasts for desert elevations.
• MyRadar: Live radar for storm tracking — critical for flash flood awareness.
• Sun Surveyor: Tracks sun position to help with orientation and shadow reading.

Real Examples

Case Study 1: Sarah’s 6-Day Solo Completion

Sarah, a 34-year-old software engineer from Tempe, completed Trail 100 over six days in November. She trained for four months, hiking 12–15 miles weekly with a 25-pound pack. Her strategy: start at 5:30 AM, hike until 1 PM, rest in shade, resume at 4 PM, and camp by 7 PM.

On Day 3, she encountered a sudden dust storm in the White Tank Mountains. Visibility dropped to 50 feet. She stopped, activated her Garmin inReach to alert a friend, and waited under a rock overhang for 90 minutes. “I almost panicked,” she says. “But I’d practiced this. I knew staying put was safer than stumbling through the storm.”

She carried 4 liters of water daily and refilled at the McDowell Preserve visitor center. “I lost 7 pounds over the trip — mostly water weight. I drank constantly. I didn’t wait for thirst.”

Her biggest lesson? “Respect the desert. It doesn’t care if you’re fit, prepared, or determined. It just is. You have to adapt.”

Case Study 2: The Phoenix 100 Duo — Mark and Elena

Mark and Elena, a married couple from Scottsdale, completed Trail 100 in 7 days with their dog, Luna, a 45-pound border collie mix. They carried extra water for Luna and used a dog-specific backpack to distribute weight.

They encountered a rattlesnake on the Estrella Trail. “It was coiled, tail rattling,” Mark recalls. “We stopped, gave it space, and waited 10 minutes until it slithered off. We didn’t try to scare it or move it. That’s when you realize you’re a guest here.”

They used a custom Google Earth overlay to track their route and shared live location updates with family. “It was the first time we ever felt truly disconnected — and it was beautiful,” Elena says. “No notifications. Just wind, rocks, and silence.”

Case Study 3: The Failed Attempt — Lessons from a Near-Miss

In March 2023, a 28-year-old hiker attempted Trail 100 in a single day. He started at 7 AM with only 2 liters of water, no GPS, and a phone for navigation. By 2 PM, he was disoriented near the Salt River, suffering from heat exhaustion.

He called 911 using his phone’s last bit of battery. Rescuers found him 4 miles off-route, dehydrated and confused. He spent three days in the hospital.

“I thought I knew the desert,” he later wrote in a forum post. “I didn’t. I thought I was tough. I wasn’t. Trail 100 doesn’t reward bravado. It rewards humility.”

FAQs

Is Trail 100 officially recognized by the National Park Service?

No. Trail 100 is an unofficial route created by local hikers and does not have federal designation. It is not part of the National Trails System. However, it passes through multiple protected areas managed by Maricopa County and the City of Phoenix.

Can I hike Trail 100 with a dog?

Yes, but with restrictions. Dogs must be leashed in South Mountain Park, Estrella Mountain Regional Park, and McDowell Sonoran Preserve. Water availability is limited — carry extra for your pet. Avoid hiking during peak heat. Some trails prohibit dogs — always check regulations per segment.

How much water should I carry per day?

Minimum 3–4 liters per person. In summer months, 5–6 liters may be necessary. Never rely on natural water sources — they are unreliable and often contaminated.

Are there water refill stations on Trail 100?

Yes, but only at specific locations: South Mountain’s Dobbins Lookout, McDowell Sonoran Preserve’s Gateway Visitor Center, and the Estrella Mountain Visitor Center. Do not assume water is available elsewhere.

What’s the best way to train for Trail 100?

Start with weekly 10-mile hikes with elevation gain. Gradually increase distance and pack weight. Include sand, rock, and steep terrain. Practice navigation with a map and compass. Train in the same season you plan to hike.

Can I camp anywhere along Trail 100?

No. Dispersed camping is prohibited in most areas. Use designated backcountry sites in White Tank Mountains Regional Park and obtain a permit. In other zones, you must day hike and exit to a trailhead each night.

Is Trail 100 suitable for beginners?

No. Trail 100 is an advanced, multi-day desert trek. Beginners should first complete several 10–15 mile day hikes in Phoenix-area parks and gain experience with navigation, hydration, and heat management before attempting this route.

What should I do if I see a desert tortoise?

Observe from a distance. Do not touch, move, or disturb it. Desert tortoises are federally protected. If injured, call Arizona Game and Fish at (623) 236-7201.

Is there cell service on Trail 100?

Spotty at best. Expect no service in the McDowell Mountains, White Tank Mountains, and remote washes. Always carry a satellite communicator.

What’s the best time of day to cross washes?

Early morning, before temperatures rise and before any potential rain in upstream areas. Never cross a wash if the sky is darkening, even if it’s not raining where you are.

Conclusion

Hiking Trail 100 in Phoenix is not merely a physical challenge — it is a profound encounter with one of North America’s most resilient and misunderstood ecosystems. This route demands more than endurance; it requires humility, preparation, and deep respect for the land. Every step you take across the Sonoran Desert is a step through time — past ancient Hohokam petroglyphs, through centuries-old saguaro forests, and into the quiet solitude where only wind and rock remain.

The journey is not about speed or distance. It’s about presence. It’s about learning to read the land, to listen to your body, and to recognize your place within a vast, ancient landscape that has endured far longer than any human trail.

If you choose to undertake Trail 100, do so with intention. Train diligently. Pack wisely. Respect the rules. Leave no trace. And when you stand atop Tom’s Thumb at sunset, watching the shadows stretch across the desert floor, you’ll understand why this route has become a legend — not because it’s easy, but because it’s real.

Trail 100 doesn’t reward the strongest. It honors the prepared. The patient. The respectful. And for those who complete it — not just with their feet, but with their hearts — it offers something rare: a quiet, enduring connection to the desert that lasts a lifetime.