In 2010, the center of population of Florida was located in Polk County, near the city of Lake Wales.
Polk County is home to one public university, one state college, and four private universities. One Fortune 500 company—Publix Super Markets (106 in 2012)—has headquarters in the county.
The first people to call Polk County home arrived close to 12,000 years ago during the last ice age as the first paleo-indians following big game southward arrived on the peninsula of Florida. By this time, the peninsula had gone through several expansions and contractions due to changing sea level; at times the peninsula was much wider than it is today, while at other times it was almost entirely submerged with only a few small islands exposed. These first paleo-indians, nomadic hunter/gatherers who did not establish any permanent settlements, eventually gave way to the "archaic people", the ancestors of the Indians who came in contact with the Spaniards when they arrived on the peninsula. These Indians thrived on the peninsula and it is estimated that there were over 250,000 in 1492 when Columbus set sail for the New World. As was common elsewhere, contact with Europeans had a devastating effect on the Indians. Smallpox, measles, and other diseases, to which the Indians had no immunity, caused widespread epidemic and death. Those who had not succumbed to diseases such as these were often either killed or enslaved as Spanish explorers and settlers arrived. Within a few hundred years, nearly the entire pre-columbian population of Polk County had been wiped out. The remnants of these Indians joined with refugee Creek Indians from Georgia and The Carolinas to form the Seminole Indian Tribe.
For around 250 years after Ponce De Leon arrived on the peninsula, the Spanish ruled Florida. In the late 17th century, Florida went through an unstable period in which the French and British ruled the peninsula. After the American Revolution, the peninsula briefly reverted to Spanish rule. In 1819, Florida became a U.S. territory as a result of the Adams-Onis Treaty.
While Florida gained statehood in 1845, it was not until 1861 that Polk County was created from the eastern half of Hillsborough County. It was named in honor of former United States President James K. Polk.
Following the Civil War, the county commission established the county seat on donated in the central part of the county. Bartow, the county seat, was named after Francis S. Bartow, a confederate Colonel from Georgia who was the first confederate Brigade Commander to die in battle. Colonel Bartow was buried in Savannah, GA with military honors, and promoted posthumously to the rank of Brigadier General. The original name of the town was Fort Blount. Several other towns and counties in the South changed their name to Bartow. The first courthouse built in Bartow was constructed in 1867. It was replaced twice, in 1884 and in 1908. As the third courthouse to stand on the site, the present structure houses the Polk County Historical Museum and Genealogical Library.
Growth in Polk County is driven by proximity to both the Tampa and Orlando metropolitan areas along the Interstate 4 corridor. Recent growth has been heaviest in Lakeland (closest to Tampa) and the Northeast areas near Haines City (nearest to Orlando). From 1990-2000, unincorporated areas grew 25%, while incorporated areas grew only 11%. In addition to developing cottage communities for commuters, there is evidence in Haines City of suburban sprawl into unincorporated areas. Despite the impressive growth rate, the unemployment rate of Polk has typically been higher than that of the entire state. In August 2010, the county had an unemployment rate of 13.4% compared to 11.7% for the entire state.
Winter Haven was best known as the home of Cypress Gardens, a theme park that closed Sept. 23, 2009. The city is now home to the theme park Legoland Florida, built on the site of Cypress Gardens. Country musician Gram Parsons was from a wealthy family in Winter Haven. Winter Haven was also home to the first Publix supermarket circa 1930, and Lakeland, Florida is where Publix's Corporate Offices are located.