Palm Beach County is a county located in the state of Florida. As of the 2010 census, the population was 1,320,134, making it the third-most populous county in Florida. The largest city and county seat is West Palm Beach. Named after one of its oldest settlements, Palm Beach, the county was established in 1909, after being split from Dade County. The county's modern-day boundaries were established in 1963. Palm Beach County is included in the Miami-Fort Lauderdale-West Palm Beach, Florida metropolitan area.