There are 28 US Post Offices in Marin County serving a total of 287,513 residents equating to 10,268 residents per post office. It's estimated that approximately 458,903 packages are handled across the 28 county post offices annually. Marin County /m\u0259\u02c8r\u026an/ is a county located in the San Francisco Bay Area of the U.S. state of California. As of the 2010 census, the population was 252,409. Its county seat is San Rafael. Marin County is included in the San Francisco-Oakland-Hayward, CA Metropolitan Statistical Area (San Francisco Bay Area) across the Golden Gate Bridge from San Francisco. Marin County is well known for its natural beauty, liberal politics, and affluence. In May 2009, Marin County had the fifth highest income per capita in the United States at about $91,480. The county is governed by the Marin County Board of Supervisors. San Quentin Prison is located in the county, as is George Lucas' Skywalker Ranch. Autodesk, the publisher of AutoCAD, is also located there, as well as numerous other high-tech companies. The Marin County Civic Center was designed by Frank Lloyd Wright and draws thousands of visitors a year to guided tours of its arch and atrium design. In 1994, a new county jail facility was embedded into the hillside nearby. Marin County's natural sites include the Muir Woods redwood forest, the Marin Headlands, Stinson Beach, the Point Reyes National Seashore, and Mount Tamalpais. The United States' oldest cross country running event, the Dipsea Race, takes place annually in Marin County, attracting thousands of athletes. Mountain biking was invented on the slopes of Mount Tamalpais in Marin."