Coal Mine Trail – Henry's Ridge & Black Diamond Natural Area

The Coal Mine Trail – Henry's Ridge & Black Diamond Natural Area offers an easy hike through a diverse landscape. You'll traverse gentle hills and established paths, winding through a mix of woodland and open spaces. The route covers 4.5 miles (7.2 km) with a minimal elevation gain of 122 feet (37 metres), making it accessible for most. Expect to spend around 1 hour and 51 minutes exploring the forested ridges and natural areas. As you hike, you might spot remnants of the area's past as coal mining lands and industrial timberland, adding a historical layer to your journey. You will encounter dense forest, marshes, and occasional views through powerline clear-cuts.

This trail is generally considered easy, suitable for various skill levels. The broader Henry's Ridge and Black Diamond Natural Area features an extensive multi-use trail network, totaling between 17 and 25 miles, accommodating hikers, trail runners, and mountain bikers. While the Coal Mine Trail itself is straightforward, some other paths in the area can include quick, alternating climbs and descents. The Black Diamond Open Space, a 1,240-acre forested expanse, is part of this region, offering a protected migratory corridor for wildlife.

The area holds significant ecological value, featuring streams, peat bogs, and wetlands that support diverse wildlife. It straddles the Cedar River and Green River watersheds, containing fish-bearing streams vital for cutthroat trout, coho, sockeye, and chinook salmon. You might even spot beavers, indicating good water quality in the area. King County Parks actively engages in forest stewardship here, including invasive weed removal, thinning, and replanting, to restore and maintain a healthy ecosystem.