Sacramento is the capital city of the U.S. state of California and the seat of government of Sacramento County. It is at the confluence of the Sacramento River and the American River in the northern portion of California's expansive Central Valley. With an estimated 2011 population of 477,892, it is the sixth-largest city in California and the 35th largest city in the United States. Sacramento is the core cultural and economic center of the Sacramento metropolitan area which includes seven counties with an estimated 2009 population of 2,527,123. Its metropolitan area is the fourth largest in California after the Greater Los Angeles Area, San Francisco Bay Area, and the San Diego metropolitan area, as well as the 27th largest in the United States. In 2002, the Civil Rights Project at Harvard University conducted for TIME magazine named Sacramento “America’s Most Diverse City.”Sacramento became a city through the efforts of the Swiss immigrant John Sutter, Sr., his son John Sutter, Jr., and James W. Marshall. Sacramento grew quickly thanks to the protection of Sutter's Fort, which was established by Sutter in 1839. During the California Gold Rush, Sacramento was a major distribution point, a commercial and agricultural center, and a terminus for wagon trains, stagecoaches, riverboats, the telegraph, the Pony Express, and the First Transcontinental Railroad.