California Department of Fish and Wildlife

History of the Napa-Sonoma Marshes Wildlife Area

Originally one of the richest wetland ecosystems in the nation, the San Francisco estuary once comprised over 4,600 square miles of habitat ranging from open water mud flats to tidal salt, brackish, and fresh water marshes to associated upland grasslands and riparian areas. This area was of global importance to the millions of migrating shorebirds and waterfowl that used it, as well as the resident populations of mammals, fish, and crustaceans. Unfortunately, since the first Spanish explorers arrived, over 90% of these wetland habitats have been dramatically altered or destroyed.

Sunrise on Napa Slough and Napa River

American White Pelicans taking flight over the Huichica Creek Unit of the Napa-Sonoma Marshes Wildlife Area
Photo Courtesy of Karen Taylor, CDFW

At the northern edge of San Pablo Bay, the Napa, Sonoma, and Solano County tidal marshes have changed from an area once over 90 square miles to less than 50,000 acres presently.

The Napa-Sonoma Marshes Wildlife Area is an area of baylands, tidal sloughs and wetland habitat located primarily between the Napa River and Sonoma Creek. Over 13,000 acres is currently managed by California Department of Fish and Wildlife. Approximately 10,000 acres of this property is comprised of former evaporative salt ponds, levees, and accreted tidal lands purchased from Cargill Salt Division in 1994. These ponds are part of an extensive restoration program that is in the early stages of development involving many different partners including both state and federal agencies. The main focus of this restoration effort is to reclaim former tidal marsh areas that were originally diked many years ago. It is anticipated that selected salt ponds may continue to be managed as shallow, high salinity ponds which provide unique habitat for many avian species, especially shorebirds.

You can find more historical information by following this link to the tour guide.