It is 9,100 acres and was formed from 4 rice plantations. 2,500 acres of it are across US 17 as Huntington Beach State Park.
It was opened in 1932 by Anna and Archer M. Huntington. Anna was a sculptor and many of her pieces are on display in the gardens. With 1,444 pieces, it has the most significant collection of figurative sculptures in an outdoor setting by American artists in the world (there is a building with even more sculptures, but they did not allow photography). The Gardens are also a National Historic Landmark.