From its county population in 2000 of 6323 to its current population estimate of 6463, the county has experienced a growth change of 140.
Calhoun County was formed in 1854 and is named for John C. Calhoun, the U.S. Vice President under Presidents John Quincy Adams and Andrew Jackson.
According to local history, one political faction wanted the county seat to be in Concord, a small community in the north, and a second faction wanted it to be in Whitney. The leader of each faction agreed to "split the difference" by establishing the seat halfway between Concord and Whitney, which was eventually named Morgan.
More than 50 percent of the land in the county has been designated as prime farmland by the U.S. Department of Agriculture. The main crops are corn, oats, sorghum, and wheat.
Morgan, the county seat, was named for General Daniel Morgan, a Revolutionary War figure.