Palm Beach County is the largest county in the state of Florida in total area, and third in population. As of 2010, the county's estimated population was 1,320,134, making it the twenty-eighth most populous in the United States. Over 40 percent of the county's population lives in unincorporated areas near the Atlantic coast.
Palm Beach County is one of three counties comprising the South Florida metropolitan area. The county was formed in 1909. It is the area's second oldest. Its largest city and county seat is West Palm Beach (Central County), which has an incorporated population of over 105,000 and an unincorporated population of 250,000. Boca Raton (South County), is the second largest, having a population approaching 90,000. Boynton Beach (South County), is the third largest city, with a population nearing 70,000 residents.
With wealthy coastal towns such as Palm Beach, Jupiter, Manalapan, and Boca Raton within its limits, as well as equestrian mecca Wellington and golfing haven Palm Beach Gardens, Palm Beach County is Florida's wealthiest county, with a per capita personal income of $44,518 as of 2004.
Among the first residents in Palm Beach County were African Americans, many of whom were former slaves or immediate descendants of former slaves who had escaped to the State of Florida from slave plantations located in Alabama, Georgia and South Carolina. Runaway African slaves started coming to what was then named Spanish Florida in the late 17th century and they found refuge among the Seminole Native Americans.
Henry Flagler, who made his home in Palm Beach, was instrumental in the county's development in the early 20th century with the extension of the Florida East Coast Railway through the county from Jacksonville to Key West.
Palm Beach County was created in 1909. It was named for its first settled community, Palm Beach, in turn named for the palm trees and beaches in the area. The County was carved out of what was then the northern portion of Dade County, comprising part of the areas now occupied by Okeechobee and Broward counties, part of Martin and all of Palm Beach county, initially including all of Lake Okeechobee. The southernmost part of Palm Beach County was separated to create the northern portion of Broward County in 1915, the northwestern portion became part of Okeechobee County 1917 and southern Martin County was created from northernmost Palm Beach County in 1925. About three-quarters of Lake Okeechobee was removed from Palm Beach County in 1963 and divided up among Glades, Hendry, Martin and Okeechobee counties.
The African American population provided significant labor for the building of the county, its hotels, houses and Flagler's railroad.
Palm Beach County was among the last school districts in the nation to integrate, in 1971.