Seattle to Portland Cycling Guide: The Complete STP Route

Introduction: Why the Seattle to Portland Route Captivates Cyclists

The first time I rolled out of Seattle on my bike with Portland as my destination, I remember thinking: “Two hundred miles. What have I gotten myself into?” That was seven years ago. Since then, I’ve completed this iconic Pacific Northwest route five times, each journey revealing something new about the landscape, the cycling community, and my own capabilities on two wheels.

The Seattle to Portland (STP) route isn’t just a ride; it’s a rite of passage for cyclists in the Pacific Northwest. Whether you’re tackling it as part of the famous annual STP event with 10,000 fellow riders or setting out independently on a quiet Tuesday morning, this route offers an unforgettable experience through Washington and Oregon’s most scenic corridors. As a cycling coach and route specialist with over a decade of experience guiding riders through the region, I’ve compiled everything you need to know to make your STP adventure a success.

Route Overview: What to Expect

The Seattle to Portland route covers approximately 200-210 miles, depending on your exact starting point and the route variations you choose. Despite its length, the terrain is surprisingly manageable for prepared cyclists.

Key Statistics

• Total Distance: 200-210 miles (320-340 km)
• Elevation Gain: 4,000-5,500 feet total (varies by route)
• Terrain: Predominantly flat to rolling with several notable climbs
• Duration Options: 1 day (experienced riders), 2 days (most common), or 3+ days (leisurely pace)
• Difficulty: Moderate to challenging, depending on your pace and experience level

The route follows a general north-to-south trajectory, taking advantage of prevailing winds that typically blow from the northwest during summer months. This tailwind factor is one reason why Seattle-to-Portland is far more popular than the reverse direction.

Best Time to Ride: Timing Your Adventure

The optimal window for riding Seattle to Portland runs from May through September, with July and August offering the most reliable weather conditions.

Monthly Breakdown

May-June: Spring riding offers longer daylight hours and lighter traffic. Expect occasional rain and temperatures ranging from 55-70°F. The landscape is lush and green, making for spectacular photography.

July: Peak season. The famous STP event, organized by Cascade Bicycle Club, takes place in mid-July and attracts over 10,000 participants. If you prefer a supported ride with full rest stops and mechanical support, this is your month. Independent riders should note that some services along the route become crowded during event weekend.

August-September: Warm, dry conditions with temperatures between 65-85°F. September brings shorter days but also harvest season, with farmstands offering fresh produce along the route.

Detailed Segment Breakdown

Segment 1: Seattle to Tacoma (35-40 miles)

The opening segment sets the tone for your journey. Departing from Seattle (typically from the University of Washington campus or downtown), you’ll navigate urban cycling infrastructure before transitioning to the Interurban Trail.

Key landmarks: Boeing Field, Kent Station, Auburn

Terrain: Mostly flat with excellent bike path sections through the Green River Valley

Tips: Start early to avoid commuter traffic through Seattle. The Interurban Trail sections are well-maintained and provide a welcome buffer from vehicle traffic. Watch for trail crossings at intersections.

Services: Abundant cafes and convenience stores throughout. The Kent Station area offers a good first rest stop with restrooms and food options.

Segment 2: Tacoma to Centralia (55-60 miles)

This middle section is where many riders find their rhythm. After passing through Tacoma, you’ll enter the agricultural heartland of Washington state.

Key landmarks: Spanaway, Roy, Yelm, Tenino, Centralia

Terrain: Rolling hills with a few moderate climbs. The stretch between Yelm and Tenino includes the famous “Military Road” section with its sustained but gradual ascent.

Tips: Carry extra water through rural sections where services are sparse. The climb after Roy catches some riders off guard; maintain a steady cadence and save energy for the miles ahead.

Services: Limited between small towns. Tenino (around mile 80) is a popular lunch stop with several local restaurants. Centralia offers the last major town services before Longview.

Segment 3: Centralia to Longview (45-50 miles)

The quietest section of the route takes you through rural Lewis County and into Cowlitz County. This segment rewards patient riding with peaceful scenery and light traffic.

Key landmarks: Chehalis, Napavine, Vader, Castle Rock, Longview

Terrain: Mix of flat valley roads and gentle rollers. The descent into Longview along the Cowlitz River provides welcome relief and stunning views.

Tips: Castle Rock (home of Mount St. Helens National Volcanic Monument) makes an excellent rest stop. The Toutle River area offers scenic viewpoints if you have time to pause.

Services: Castle Rock has cafes and convenience stores. Longview offers comprehensive services including bike shops, hotels, and restaurants.

Segment 4: Longview to Portland (60-65 miles)

The final push crosses into Oregon and delivers you to the finish. This segment includes the iconic Columbia River crossing and the final miles through North Portland.

Key landmarks: Kelso, Kalama, Woodland, Ridgefield, Vancouver, Portland

Terrain: Generally flat along the Columbia River corridor with one significant climb near Woodland. The final 15 miles through Vancouver and Portland are flat but require attention to navigation.

Tips: The bridge crossing from Washington into Oregon can be windy; grip your handlebars firmly and maintain steady control. Portland traffic requires heightened awareness, but bike lanes are well-marked in most areas.

Services: Frequent towns along this corridor offer ample support. Many riders celebrate at the finish with Portland’s renowned food and craft beverage scene.

Route Options: Finding Your Ideal Path

The Interurban Trail Approach

Multiple sections of the Interurban Trail system provide car-free riding through the Seattle metropolitan area and South King County. While these trail sections add some distance, they significantly improve safety and riding enjoyment. I highly recommend taking the trail whenever possible, especially if you’re new to long-distance cycling or uncomfortable with vehicle traffic.

Back Roads vs. Highway Considerations

The traditional STP route uses a combination of secondary roads and highway shoulders. In recent years, alternative “scenic routes” have emerged that prioritize quieter back roads over faster highways.

Highway Route Benefits: More direct, better signage, familiar to STP event veterans, reliable road surfaces

Back Roads Benefits: Less traffic, more scenic, quieter riding experience, better for photography

For first-time riders, I recommend following the established STP route for its predictable services and well-documented navigation. Experienced cyclists looking for a more immersive experience should consider incorporating back road alternatives, particularly through Lewis County.

The STP Event vs. Riding Independently

The Annual STP Event

The Cascade Bicycle Club’s Seattle to Portland event is North America’s largest multi-day cycling event. Participating in STP offers several advantages:

• Full support: Rest stops every 15-20 miles with food, water, and mechanical assistance
• SAG support: Vehicle support for riders who need to stop
• Community: Riding with thousands of fellow cyclists creates an electric atmosphere
• Coordination: Luggage transport for multi-day riders
• Safety: Medical support along the route

The event typically costs $100-200 depending on registration timing and options selected. One-day and two-day options are available.

Independent Riding

Riding Seattle to Portland independently offers flexibility and solitude. You can choose your dates, pace, and route variations without adhering to event schedules. Independent riders should be self-sufficient with navigation, mechanical repairs, and nutrition.

Best for: Experienced cyclists, those who prefer quieter riding, travelers on non-standard schedules, budget-conscious riders

Accommodation Options for Multi-Day Riders

Hotels and Motels

Centralia/Chehalis Area (Mile 85-90): Multiple chain hotels including Best Western, Quality Inn, and independent motels. Book ahead during summer weekends.

Longview (Mile 140-145): Several hotel options along the main highway. The Red Lion and local motels cater to cyclists.

Camping Options

Millersylvania State Park (Mile 70): Beautiful forest camping with showers. Reservations recommended.

Lewis and Clark State Park (Mile 95): Old-growth forest setting with cyclist-friendly facilities.

Kalama River (Mile 160): Several private campgrounds offer affordable overnight options.

Budget Tips

Warmshowers.org connects cyclists with hosts offering free accommodation. Many cycling-friendly communities along the route have generous hosts who understand long-distance riding.

Safety Tips: Arriving Without Incident

Traffic Awareness

While most of the route follows cycling-friendly roads, several sections require heightened vigilance:

• Urban Seattle: Heavy traffic, complex intersections; follow bike route signage carefully
• Highway 99 sections: Fast-moving vehicles; use rear lights and wear high-visibility clothing
• Columbia River bridges: Narrow shoulders, potential crosswinds; maintain control and stay alert
• Portland approach: Urban traffic; follow established bike routes and signal intentions clearly

Weather Variability

Pacific Northwest weather changes rapidly. Even during summer, conditions can shift from sunny and warm to cool and rainy within hours.

Essential precautions:

• Carry a lightweight rain jacket regardless of forecast
• Arm warmers and leg warmers pack small but provide significant comfort
• Start with removable layers you can shed as temperatures rise
• Apply sunscreen even on overcast days; UV exposure is significant

Gear Recommendations

Bike Setup

A road bike or gravel bike with reliable components is ideal. Ensure your bike is serviced before departure, with special attention to:

• Tires: Fresh rubber rated for 200+ miles; carry spare tubes and patch kit
• Brakes: Full pad life remaining; test in wet conditions before the ride
• Drivetrain: Clean chain, properly adjusted derailleurs
• Lights: Front and rear lights, charged and ready (required for early starts and late finishes)

Essential Gear Checklist

• Helmet (required in Washington and Oregon)
• Cycling computer or GPS device with route loaded
• Two water bottles minimum (three for hot days)
• Multi-tool and tire levers
• Pump or CO2 inflator
• Phone with backup battery
• Cash and cards for roadside purchases
• Sunglasses and sunscreen
• Rain jacket
• Arm and leg warmers

Nutrition Strategy

For a ride of this duration, nutrition planning is critical. Aim to consume 200-300 calories per hour through a mix of real food and cycling-specific products. Bring enough supplies to cover gaps between services, typically 20-30 miles.

Planning Your Pacific Northwest Cycling Adventure

The Seattle to Portland route serves as an excellent introduction to long-distance cycling in the Pacific Northwest. Once you’ve conquered STP, you’ll be well-prepared for the region’s other legendary routes.

Consider exploring the Pacific Coast Highway cycling route, which offers stunning coastal scenery and can be combined with an STP finish for an epic multi-week adventure. For a different experience, the San Juan Islands by Ferry and Bike provides a more relaxed island-hopping journey perfect for recovery after your STP accomplishment.

Final Thoughts: Your STP Journey Awaits

Whether you choose the camaraderie of the annual event or the independence of a solo adventure, the Seattle to Portland route delivers an unforgettable cycling experience. The key to success lies in proper preparation: train adequately, plan your logistics carefully, and maintain flexibility for the unexpected.

I still remember crossing the finish line in Portland on my first STP, exhausted but exhilarated. The journey had tested my limits, introduced me to fellow cyclists who became lifelong friends, and shown me landscapes I’d driven past countless times without truly seeing. That transformative experience is waiting for you.

Start planning your Seattle to Portland adventure today. The road between these two great cities has been calling cyclists for decades, and it’s ready for you.

Last updated: January 2026. Route conditions and event details may change; verify current information before your ride.