The first European-Americans settlers arrived in Carthage and Hancock County in the first few decades of the 19th century. By 1833, they had erected simple buildings in Carthage, and the town was platted in 1838. By this time Carthage had been designated as the county seat of Hancock County. The only person legally hanged in Hancock County, Efram Fraim, was defended in his trial by roaming country attorney Abraham Lincoln.

Fraim was found guilty of murder. Lincoln filed an appeal with the judge in the trial, which was as far as appeals in those days mostly went. Because at the time Carthage had no jail, Fraim was kept at the Courthouse, which was next to the school. Fraim would converse with the children from his second-floor window.

As a result of these conversations, most of the school children were present when their new friend, Efram, was hanged. The hanging is believed to have taken place near the current city sewer plant east of town, where a natural amphitheater allowed for a crowd to view the spectacle. While incarcerated in the Carthage Jail in June 1844, Joseph Smith, founder of the Latter Day Saint movement, and his brother Hyrum Smith were killed by a mob on Thursday, June 27, 1844. On October 22, 1858, Abraham Lincoln spoke in Carthage while campaigning for the Senate.

A large stone on the south side of the Courthouse square commemorates the spot. Over the years the jail had been modified and used for different purposes. For a period the jail was home to Carthage College. The jail has been restored to a close approximation of its appearance in 1844 and is now owned by the Church of Jesus Christ of Latter-day Saints.

The site, a full city block, is a historical visitor's center. Regionally noted botanist, philanthropist, and traveler Dr. Alice L. Kibbe called Carthage home. Along with Dr. Kibbe's personal collections, Carthage's Kibbe Hancock Heritage Museum houses a variety of exhibits celebrating local and regional history. Carthage is the only city in Illinois to have all of the jails ever used still in existence: The old jail, called the Mormon Jail; the jail next built which was also the Sheriff's residence and is on the south side of the Courthouse square; and the new jail, on Highway 136 on the city's west side. The Hancock County Courthouse in Carthage, built in 1908, is the third courthouse for the county.

It is at the center of the square in Carthage. The courthouse and shops surrounding the square have been listed on the National Register of Historic Places since 1986.