How Onarga received its name remains a mystery. Realists believe Illinois Central Railroad land commissioner John Calhoun combined two or three consonants and added the necessary vowels to invent a nice-sounding town name. Many prairie towns in the 1850s, with the arrival of the railroads, received their names by this method. Romantics believe Onarga was named for a young Native American girl, Princess Onarga, daughter of an Iroquois Indian chief. Prior to the construction of the Illinois Central Railroad, Native Americans controlled this part of Illinois, and among the roving tribes that crisscrossed the grand prairie were the powerful Iroquois. Legend says that when a name was proposed for the new town on the railroad, none better than Onarga was given. This mystery may never be solved, but the realists and romantics agree to disagree—agreeing foremost on celebrating and preserving the rich history of Onarga.