Union Falls

Grassy Lake trailhead to Union Falls overlook

The NPS route narrative gives intermediate campsite and junction distances rather than one unambiguous total. Plan the entire route with a current map rather than adding those approximate segments.

Unbridged swift-water crossing, remote forest trail and slippery waterfall terrain. The older NPS narrative describes difficult road travel and recommends high clearance; its historical swimming and reservation details are not current guidance.

Where to start

Grassy Lake trailhead parking is on the north side of Grassy Lake Road at the reservoir’s western edge. The trail leaves the lot’s west side.

Timing & water

NPS update October 25, 2026 reports wet, snowy and icy trails. Grassy Lake Road was reported open June 3; verify current seasonal road status. A beaver-dam-affected area west of campsite 9U1 requires caution.

Before you go

Obtain current Yellowstone wilderness camping permits if staying overnight; do not rely on the 2012 blog’s booking procedure.