Lake Merwin

Lake Merwin in Washington

The center of the lake is at 45.9567, -122.5550. The deepest point on record is about 190 feet. It lies at roughly 236 feet of elevation. Outflow feeds the Lewis River.

The federal and state datasets behind this guide list no named beach at Lake Merwin. That does not mean there is no access, only that none is catalogued. If you need a named beach, Columbia River Gorge National Scenic Area on Columbia Gorge is some 53 miles from here. Shoreline access on lakes like this one is often informal and unsigned.

Nearby water includes Yale Lake (Washington, 11 mi), Swift Reservoir (Washington, 19 mi) and Vancouver Lake (Washington, 21 mi). Washington has 45 lakes on this site in total.

No public sensor reports water temperature at Lake Merwin, so the panel shows air temperature and wind. Most Washington day-use areas open for the summer season and close outside it. Water quality is monitored unevenly on inland lakes, so posted notices are the most reliable guide.

Station 14219950, LAKE MERWIN NEAR CHELATCHIE, WA, publishes the water surface elevation used here. Over the record shown on the level page the gauge has moved between 221.96 ft and 238.92 ft (low on 2025-09-29, high on 2026-04-27). The last value stored here, 233.00 ft, is from 2026-09-09. A falling pool widens the beaches and shortens the ramps, so it is worth checking before you drive out.