Sacramento is the capital city of the U.S. state of California and the seat of Sacramento County. Located at the confluence of the Sacramento River and the American River in Northern California's Sacramento Valley, Sacramento's estimated 2018 population of 501,334 makes it the sixth-largest city in California and the ninth largest capital in the United States. Sacramento is the seat of the California Assembly, the Governor of California, and Supreme Court of California, making it the state's political center and a hub for lobbying and think tanks. Sacramento is also the cultural and economic core of the Sacramento metropolitan area, which had 2010 population of 2,414,783, making it the fifth largest in California.