Sacramento–San Joaquin is a freshwater ecoregion in California. It includes the Sacramento and San Joaquin river systems of California's Central Valley, which converge in the inland Sacramento–San Joaquin Delta. It also includes the mostly-closed Tulare Lake basin in the southern Central Valley, the rivers and streams that empty into San Francisco Bay, and the Pajaro and Salinas river systems of Central California which empty into Monterey Bay.