Sunset Lake

Overview

Sunset Lake is a large, shallow thermal pool on the Black Sand Basin boardwalk near Old Faithful. You don’t hike to it—just stroll the signed loop and it appears in all its glassy, blue calm. Despite the “lake” name, it’s a hot spring, not for touching or soaking.

What You’ll See

Expect a broad, ombré pool with a striking deep-blue center. Its color comes from clear, hot water absorbing light rather than colorful microbial mats—high, consistent temperatures keep most mats from forming along the edges. It’s an underrated stop in a very popular neighborhood, and an easy win for photographers.

Logistics

• Access via the Black Sand Basin parking area along the Grand Loop Road near Old Faithful, then follow the boardwalk loop.
• There’s no separate trailhead—Sunset Lake is on the signed boardwalk.
• No restrooms at Black Sand Basin; the nearest options are in the Old Faithful area or at nearby basins with vault toilets.

Best Time to Visit

• For color: view it under full sun—late morning to mid‑afternoon shows the blue best.
• For parking and a calmer boardwalk: aim for early morning or later in the day, as the lot tends to fill mid‑day.

Wildlife & Safety

Thermal basins often attract bison and elk; give them plenty of space and never block their path. Stay on the boardwalk—ground can be thin and water near boiling. Soaking in thermal features is illegal.