There are 4 US Post Offices in Whitley County serving a total of 36,162 residents equating to 9,041 residents per post office. It's estimated that approximately 57,719 packages are handled across the 4 county post offices annually. Whitley County is a county located in the U.S. state of Indiana. As of the 2010 census, the population was 33,292. The county seat is Columbia City. The county has the highest county number (92) on Indiana license plates, as it is alphabetically the last in the list of counties."