Huichica Creek Unit Professional Review and Guide
"The Napa-Sonoma Marsh covers 48,000 acres on the north edge of San Pablo Bay. The marsh lies between Highway 12 on the north and Highway 37 on the south, straddling Napa, Sonoma, and Solano counties. Within the marsh are saltwater ponds, tidal marshes, seasonally flooded wetlands, agricultural fields, sloughs, and rivers. The rich wetland is fed by the Napa River, which drains Napa Valley, and Sonoma Creek, which drains Sonoma Valley. It is an important habitat for fish, shorebirds, and waterfowl and is a premier place to observe wildlife. The tidal marsh was diked for agricultural uses in the late 1800s and early 1900s. In the early 1950s the Leslie Salt Company purchased much of the land and developed it for salt production."