The desert community of Lost Lake, also known as Lost Lake Resort and Lost Lake Landing, lies along the west shore of the Colorado River. It also lies along U.S. Route 95 near the northeast extent of Riverside County. Official U.S. Geological Survey feature ID is 245216 and NAD27 coordinates for the community are 34°00?44?N 114°28?27?W? / ?34.01222°N 114.47417°W? / 34.01222; -114.47417Coordinates: 34°00?44?N 114°28?27?W? / ?34.01222°N 114.47417°W? / 34.01222; -114.47417. The community lies at the foot of Riverside Mountain, 34°00?49?N 114°30?45?W? / ?34.01361°N 114.5125°W? / 34.01361; -114.5125? (Riverside Mountain), with a summit measuring 2,127 feet. The community is named for a lake, Lost Lake, located at 34°01?20?N 114°28?21?W? / ?34.02222°N 114.4725°W? / 34.02222; -114.4725? (Lost Lake).