Meiss Lake is a 3,000-acre (12 km²), shallow, warm lake located in the western portion of Butte Valley, in eastern Siskiyou County. The lake is a remnant of a larger lake that occupied the entire valley when temperatures were cooler and is fed seasonally by several creeks in Butte Valley. Although Meiss Lake is in the closed Butte Creek Valley basin, in wetter times it undoubtedly flowed over a low divide into Rock Creek and then into the Klamath River east of Copco Lake. A pumping station was installed during the 1964 floods to evacuate floodwaters into Rock Creek as protection for nearby croplands and wildlife habitat wetlands.