The Rush Creek Open Space Preserve is a nature reserve near Novato, California. It is named for Rush Creek. The 522-acre (2.11 km) lot of public land has a host of hiking trails as well as a marsh in the center, and is bordered by various marshes and shallow lakes owned by the California Department of Fish and Game. Due to the proximity of marshes and shallow lakes, a multitude of birds and waterfowl live in the area, with close to 200 species. This makes the preserve a popular destination for birdspotters. The preserve is also popular for running, hiking, biking, dog walking, and horse riding, as all are allowed on most of the trails. A rare blue oak woodland is also located near the Bahia Marsh.

The 632-acre (2.56 km) acre lot was purchased by the Marin Audubon Society, who donated most of the land to several government entities, with the majority of it going to the Marin County Open Space District and the California Department of Fish and Wildlife. The Audubon Society still own much of the land around the Bahia Marsh and the preserve.

During the 2011-2017 California drought, Rush Creek and its lakes were completely dried out, however they have since returned back to their natural state.