Castaic Lake Recreation Area is a reservoir of the California State Water Project. It is one of the California State Water Project s largest recreational lakes and the terminal of its west branch. The site includes a shoreline of more than 25 miles. Castaic Lake Recreation Area s major attraction is the 425-foot tall Castaic Dam. Castaic Lake Recreation Area has two bodies of water that include Lower Lake and Upper Lake. Lower Lake is for nonpower boating and canoeing activities. Swimming season on Lower Lake runs from mid-May to mid-September. Upper Lake is for sailing, power boating, water and jet skiing and fishing activities. Its lakes are stocked with basses, trouts and catfish. Castaic Lake Recreation Area s other recreational activities include hiking and biking trails, as well as features picnic areas and playgrounds. Rental group picnic areas are available for up to 600 persons.