The Caswell Memorial State Park is a state park in Ripon, California. It is situated along the Stanislaus River.

Named after and in honor of the former landowner, Thomas Caswell, the Caswell Memorial State Park has always been intended to be protected from development and destruction. Caswell always wanted to preserve the beautiful forest and setup of the area, so to ensure this, his children donated the land to the people of California. It was turned into a state park in 1958.

The Caswell Memorial State Park is best noted for protecting a riparian oak woodland. This particular kind of habitat is dwindling in number today, making it important to preserve what is still left. The site is also home to several endangered animals like the riparian brush rabbit.