Polk County, named for the eleventh president of the United States, is located in central Florida and is one of the largest counties in the state, being 1,200 square miles larger than Rhode Island. It became Florida's 39th county on February 8, 1861 when Governor Madison S. Perry signed the legislation that created it. By the same act, Hillsborough County lost about half of its eastern area and became smaller than its new neighbor. Polk also added bits and pieces on its eastern Kissimmee River border when land was taken from Brevard County Prior to the establishment of Polk County, the counties of central Florida went through a number of changes. The original counties were subdivided as settlers from the Carolinas and Georgia arrived to take advantage of the grazing lands for cattle, woodlands of longleaf pine, and other natural resources. Some of these settlers were making their second and third moves as they migrated further south in the state. It took several years of strenuous politicking by frontier residents who needed a courthouse and a local government to create Polk County. Counties in Florida did not spring full blown as we see them today, but developed as population growth required that government services be closer to population centers. Thus, one can trace the influx of settlers to an area by the dates in which new counties were added and existing boundaries changed. What is now Polk County evolved from St. Johns County over a period of time as shown below:

1822 - Duval County was cut from St. Johns County

1823 - Monroe County was cut from St.Johns County

1824 - Alachua County was cut from Duval and St. Johns Counties

1834 - Hillsborough County came from Alachua and Monroe Counties

1861 - Polk County was formed from Hillsborough and Brevard Counties

1871 - Polk County's eastern boundary on the Kissimmee River was changed in

1887 - Osceola County became a border of Polk County when it was created from Orange and Brevard Counties.

It is important for genealogists to consider changes in local boundaries when they do their research as various vital records and property deeds may not be found where expected. For example, some of the records for Polk County prior to 1861 are in Hillsborough County.