Lone Star Basin, officially called Third Geyser Basin, is one of the smallest geyser basins of Yellowstone. It comprises only a few geysers and a few hot pools of size. Spread over a distance of roughly 2 km (1.4 miles) along Firehole River south of Upper Basin, it can be reached via an old, paved road, starting 4 km (2.5 miles) north at Kepler Cascades. The road is open to pedestrians and bicyclists, but not to motorized vehicles. On your way to Lone Star Basin you pass Halfway Spring, a perpetual spouter, after approximately 1.2 km (0,7 miles). It lies west of the road at the end of a small clearance.

Lone Star Basin is divided up into five groups and all of them but Lone Star Group, the most prominent one, are true backcountry settings. If you visit these groups, you should take care accordingly. A visit of Lone Star Basin can be perfectly combined with a subsequent hike to Shoshone Geyser Basin 9.5 km (6 miles) farther south.