Great Valley Grasslands State Park is a state park of California, United States, preserving a parcel of remnant native grassland in the San Joaquin Valley. Such a temperate grasslands, savannas, and shrublands biome was once widespread throughout the whole Central Valley. The 2826 acre park was established in 1982. Largely undeveloped, it was formed by combining two former state park units: San Luis Island and Fremont Ford State Recreation Area. Its chief attractions for visitors are spring wildflowers, fishing, and wildlife watching.

Grassland Ecological Area

The park is part of the larger Grasslands Ecological Area (GEA), a 65,000 ha of federal, state, and private lands dedicated to wildlife conservation. In 2005, the GEA earned recognition as a Ramsar Wetland of International Importance, underscoring its status as California's largest remaining contiguous freshwater wetland system. Located in the San Joaquin River Basin of the Central Valley, this diverse landscape encompasses a rich tapestry of habitats, from semipermanent and permanent marshes to riparian corridors, vernal pools, wet meadows, native uplands, and expansive grasslands. The ecological significance of the GEA is particularly evident during winter months when it transforms into a crucial haven for migratory birds. Annually, the area hosts hundreds of thousands of waterbirds, including a wide variety of duck and goose species, alongside vast numbers of shorebirds. Beyond its role as a migratory stopover, the GEA serves as a sanctuary for numerous threatened and endangered species. This remarkable concentration of diverse ecosystems within the GEA fosters an extraordinary richness of flora and fauna, positioning the area as a cornerstone of California's biodiversity conservation efforts.

Flora and fauna

Several rare and endangered species inhabit the park.

Proposal for closure

Great Valley Grasslands State Park faced significant challenges in January 2008 when it was one of 48 California state parks proposed for closure as part of a statewide deficit reduction program. This proposal underscored the ongoing financial pressures affecting California's park system. Ultimately, the threatened closures were avoided through budget adjustments, including reduced operating hours and cutbacks in maintenance across the state park system. Since then, the park has not only remained open but has also become a focal point for renewed conservation efforts. As of 2024, California State Parks has initiated a comprehensive General Plan process for Great Valley Grasslands State Park, aimed at enhancing visitor experiences and addressing resource management needs.