Winter Haven is a city in Polk County, Florida, United States. The population was 33,874 at the 2010 census.
The Timucua and the Calusa were the earliest known inhabitants of the land that would become Winter Haven. Both of these groups were deeply impacted, by war and disease, from the Spanish exploration of Florida in the early 1500s. In 1819, after the signing of the Adams-Onís Treaty, the United States gained control of Florida. The first American or European settlers in the area were encouraged to settle here by the Armed Occupation Act of 1842. This act was specifically created to increase the white population in the area as a way to weaken the Native Americans populations after the Second Seminole War. It created generous land grants and other incentives for settlers who were willing to defend themselves against the native populations, hence the name of the act.The arrival of the railroad created the first real growth in area. The area was platted in 1884 and would first be known as Harris Corners. This name was in reference to F.A.K. Harris, who opened the first mercantile store in the area around this time. The name Winter Haven was later suggested, in reference to the area's pleasant climate.