Sunshine and Fourmile Canyons to Gold Hill loop

This loop is a mixed-surface ride, featuring significant sections of unpaved gravel and dirt roads alongside paved segments. While skilled road cyclists have completed it on narrow tires, a gravel bike or a robust road bike with wider tires (32mm or more) and low gears is highly recommended for a more comfortable and enjoyable experience.

The average duration for this challenging 36.9 km (22.9 miles) loop is around 3 hours and 20 minutes. However, this can vary significantly based on your fitness level, the type of bike you're riding, and how often you stop to enjoy the views.

The loop typically starts near downtown Boulder, offering various parking options. Many cyclists begin from public parking areas in Boulder, such as those near the Boulder Creek Path, which is part of the route. Specific parking availability can vary, so it's advisable to check local parking regulations before your visit.

No, this loop is considered difficult and is generally not suitable for beginners. It involves significant elevation gain (over 1,000 meters or 3,000 feet) with steep, sustained climbs, some reaching 9-13% gradient. The mixed-surface terrain also adds to the challenge, requiring good bike handling skills.

The loop offers diverse and stunning scenery. You'll ride through winding roads, meadows, forests, and along creeks. Highlights include the upper sections of Sunshine Canyon (Gravel Section) with views of the Indian Peaks, the picturesque Fourmile Canyon (Boulder Canyon to Poorman), and panoramic views of the Rocky Mountains as you ascend towards Gold Hill. The historic mining town of Gold Hill itself, with its rustic buildings and the Gold Hill General Store, is also a notable point of interest.

The best time to cycle this loop is typically from late spring through early fall (May to October), when the weather is generally mild and the roads are clear of snow and ice. Summer offers warmer temperatures, while spring and fall provide cooler riding conditions and beautiful foliage. Always check local weather forecasts, especially for mountain conditions, before heading out.

The route is known for its mixed-surface terrain. You'll encounter a significant mix of paved, unpaved gravel, and dirt roads. Approximately 47-53% of the route can be unpaved. Sections like Sunshine Canyon and the climb from Fourmile Canyon up to Gold Hill via Gold Run Road include steep dirt and gravel segments. Be prepared for varied conditions under your tires.

Yes, this trail is located within Boulder Open Space and Mountain Parks (OSMP). While there are generally no entrance fees for OSMP, specific regulations apply to preserve the natural environment and ensure visitor safety. These can include rules regarding trail use, speed limits, and respecting wildlife. Always check the official OSMP website for the most current regulations before your ride.

As a road and gravel cycling route, this loop is primarily designed for cyclists. While some sections may pass through areas where dogs are permitted on leash, it's not typically considered a dog-friendly cycling trail due to the nature of the ride (speed, traffic, mixed surfaces). If you plan to bring a dog, ensure they are safely secured and that you comply with all local leash laws and regulations for Boulder Open Space and Mountain Parks.

Yes, the historic Gold Hill General Store in the town of Gold Hill is a popular stop for cyclists. It offers a chance to grab snacks, drinks, and a brief rest before continuing your journey. Otherwise, plan to carry sufficient water and nutrition for the duration of the ride, as other amenities are limited once you leave Boulder.

Given the difficulty and mixed terrain, you should bring plenty of water, energy snacks, a repair kit (including spare tubes and a pump), and appropriate cycling attire for varying weather conditions. A helmet is essential. Consider bringing a GPS device or a fully charged phone with the route downloaded, as cell service can be spotty in some canyon areas. Wide tires (32mm+) and low gears are also highly recommended for your bike.