Laguna Lake a lake and seasonal reservoir in the upper Los Osos Valley, in San Luis Obispo, California. It lies at an elevation . It is supplied with water from various small watercourses from the surrounding valley but especially by Prefumo Creek a tributary of San Luis Obispo Creek that enters the lake at . The Lake is also drained by Prefumo Creek at from its eastern end at that drains to San Luis Obispo Creek.
The Rancho Laguna a section of Mission San Luis Obispo lands originally enclosed the lake.