Besides serving as a water supply for the area, the lake is used for rowing, paddling, and fishing. Santa Clara County manages the 960-acre Lexington Reservoir County Park. The park provides facilities for hiking and picnicking. The reservoir is stocked with black bass, trout, bluegill, and crappie. The park includes part of the San Andreas Fault, which crosses Los Gatos Creek just south of the upstream end of the reservoir. The mountains feature redwood forests, chaparral, grasslands, hardwoods, and mixed conifer habitats.
When the level of Lexington Reservoir drops, it is possible to see portions of the old roads that were used in the construction of the reservoir and to the historic towns of Lexington and Alma that once existed in the valley before the reservoir was created. Some building foundations in the ghost towns are also visible at times.