Palm Beach County is located in southeastern Florida along the Atlantic Coast, stretching from the ocean beaches westward to Lake Okeechobee and the upper Everglades. Palm Beach County was officially created on April 30, 1909 out of the northern part of Dade County, which, in those days, stretched as far north as Brevard County and included all of Lake Okeechobee to the west. These days, while Palm Beach County is still the largest county in Florida in land area, it only contains 1,974 square miles in land and 412 square miles of water surface. Portions of that original Palm Beach County went into the creation of Okeechobee, Broward, Martin, Glades and Hendry Counties. The county seat is West Palm Beach.

Henry Flagler, builder of the Florida East Coast Railway, lived in Palm Beach for many years. Palm Beach County is home to the Arthur R. Marshall Loxahatchee National Wildlife Refuge.

Palm Beach County is the third most populous county in Florida, 29th most populous in the United States. Over 40% of the population lives in a narrow strip of unincorporated land along the Atlantic coast.