The first census of the State of Florida was taken in the summer of 1845. The census takers were slow in making their returns, and data for only 17 of the 26 counties were submitted to the adjourned session of the General Assembly, which met in November. The census was actually taken, however, in every county except St. Lucia and Dade, a total of 66,381 inhabitants being reported.
"Florida's Population in 1845,"
Florida Historical Quarterly: Vol. 24
, Article 5.
Available at: https://stars.library.ucf.edu/fhq/vol24/iss1/5