Ruth Lake

Ruth Lake is a seven-mile reservoir on the Mad River in southern Trinity County, about 70 miles from Eureka, and a water supply for the Humboldt Bay region.

Mussel rules

Every boat and flotation device must be inspected before entering the lake, and every watercraft must be registered, inspected and carry a valid 2026 sticker. Owners fill out a watercraft survey. Since April 3, 2026, boats with ballast tanks or anything that can't be drained, like wakeboard boats, automatically fail inspection and need the mandatory 30-day red quarantine band from Ruth Lake Marina or Ruth Rec Campground. Boats that fail inspection also go into the 30-day quarantine.

On the water

Ruth Lake Marina is open April 1 to October 31, 7 a.m. to 7 p.m., with a two-lane paved ramp, a courtesy dock, gas, tackle and licenses, fishing and patio boat rentals, and wet moorage and dry storage. Boating, waterskiing and swimming are all popular, and the lake holds rainbow trout, bass and crappie.

Camping

Ruth Rec Campground has 96 sites with a launch ramp, courtesy dock, kayak and canoe rentals and showers; Hobart Creek and Boy Scout Cove are smaller. Old Ruth, Sheriff's Cove and Blue Slide are day-use areas open 8 a.m. to 8 p.m.