The Sacramento-San Joaquin River Delta is an example of an inverted river delta, one of only a few worldwide. It is the largest estuary on the United States' Pacific Coast.
The fan-like area of the delta moves downstream, as the two rivers are forced to exit the Central Valley through the Coast Range via the narrow channel known as the Carquinez Strait, which leads to the San Francisco Bay and mainly the Pacific Ocean through the Golden Gate. The delta consists of myriad small natural and man-made channels (locally called sloughs), creating a system of isolated lowland islands and wetlands defined by dikes or levees. The delta islands are not islands in the classic sense, but are referred to as such because they are completely surrounded by water and are so isolated in many cases that they are accessible only by boat, ferry or aircraft. An extensive system of earthen levees has allowed widespread farming throughout the delta. Its peat soil makes it one of the most fertile agricultural areas in California and arguably even the nation, contributing billions of dollars to the state's economy. Certain specialty crops, such as asparagus, are grown in the delta in quantities unmatched anywhere else in the United States. The delta and its "Thousand Miles of Waterways" are a recreation destination. The warm, breezy summers are popular among water skiers and boaters and even the chilly, foggy winters draw fishermen and hunters. Source: Wikipedia