Deerfield Beach is a city in Broward County, Florida, USA. The city is named for the numerous deer that once roamed the area. As of the 2010 United States Census, the population was 75,018. It is part of the Miami metropolitan area, which was home to 5,564,635 people at the 2010 census. Deerfield Beach's history dates back to 1890 when a small settlement named Hillsborough was developed along the Hillsboro River. As the population grew to 20 by 1898, the settlement was now served by its own post office and the town was named Deerfield for the deer that grazed along the Hillsboro River.