Hansen Dam is a large earthfill dam located in the San Fernando Valley region of Los Angeles, California. Completed in 1940, it was built to provide flood control, water conservation, and recreational opportunities. The dam creates the Hansen Dam Recreation Area, which includes a lake, picnic areas, and trails for hiking and biking. The dam is named after Henry Hansen, a prominent figure in the development of the Los Angeles water system. It plays a crucial role in managing stormwater runoff and protecting surrounding communities from flooding. The area is also popular for outdoor activities, attracting visitors year-round.