When the U.S. first took over the state of Florida, there was East Florida, with its capital at St. Augustine, and West Florida, with its capital at Pensacola. Yet, in 1824, when Florida became a part of the United States, neither of these locations made geographical sense.
These two capitals were separated by 400 miles in a time before automobiles. This would account for around 20 days' travel, so the leaders decided that a new capital was needed.
This was why John Lee Williams and Dr. William Simmons went on the hunt for a new site, and eventually agreed that a former native American settlement in the area of what's now Tallahassee would be the ideal position for the new capital.