Shadow Cliffs Regional Recreation Area is a regional park on the border of Pleasanton, California, and Livermore, California that is part of the East Bay Regional Parks (EBRP) system on Stanley Blvd. The lake was once a gravel pit, but then included a sandy beach with swimming, water slides and it supports fishing and recreational boating. Now the water slides have been taken down and is now planned to be replaced by an Interpretive Center.