Carrol county was established in 1828 and named for Charles Carroll, the last surviving signer of the Declaration of Independence. Carroll County’s roots extend back to the Northwest Territory in 1787, and later, the Indiana Territory in 1800. Settlers began cultivating the area from 1824 and was officially authorized on January 17, 1828. Delphi the county seat was platted in 1828 by General Samuel Milroy on land donated by William Wilson.. Originally named Carrollton, the town adopted the name Delphi, drawing inspiration from the ancient city in Greece.  As of the 2020 census the population of Carroll county was 20,306.