Diablo Lake

Diablo Lake explained

The center of the lake is at 48.7142, -121.1310. Maximum depth is around 390 feet. It lies at roughly 1,201 feet of elevation. The Skagit River carries the outflow.

Station 12176500, DIABLO RESERVOIR NEAR NEWHALEM, WA, publishes the water surface elevation used here. The last value stored here, 1,201.27 ft, is from 2026-09-09. A low pool exposes stumps and mud in the shallow arms of the lake.

Baker Lake / Middle Fork Nooksack, on Baker Lake, is the closest named beach in this guide, about 28 miles off. Where there is no marked beach, entry is usually from a boat ramp or an unimproved bank. No named swimming beach is mapped at Diablo Lake in the federal and state datasets this guide reads. Access is through whatever the operating agency provides on the ground, so check with them first.

The closest lakes in this guide are Ross Lake (Washington, 8 mi), Lower Granite Lake (Washington, 19 mi) and Baker Lake (Washington, 23 mi). Washington has 45 lakes on this site in total.

Season dates vary by park; the operating agency publishes them each spring. Water temperature is not measured at this lake by any public agency we read. Check the operating agency for advisories before any water contact, especially for blue-green algae in late summer.