Knox County was created on June 10, 1830, in the Fifth Judicial District of the Circuit Court by Judge Richard M. Young when he was presented the petition by a committee of five men with the proof of 350 residents which was required to form a county. It is recorded that the first families arrived from Kentucky in 1828. The log village they erected was near and on the Henderson property of Mr. And Mrs. Allen Freberg and was referred to as the Gum Settlement or the Henderson Group. There were two areas known as Henderson; one the Henderson Group and the other Henderson Town. The post office changed the name of Henderson Town to Knoxville in 1837. In the Maquon history it is noted that William Palmer built a log cabin in 1827. The first marriage license recorded was 1830. The first birth and death was recorded in 1878. Knoxville was the first county seat. There was a long dispute, lasting many years to move the county seat. The official confirmation from the Illinois Supreme Court came early in 1872 which moved the seat to Galesburg. Knox County was named for General Henry Knox, Chief of Artillery in the Revolutionary Army, and later Secretary of War in George Washington’s first cabinet.
The Knox County Courthouse in Galesburg was erected in 1884-1886, more than a decade after the removal of the County Seat from Knoxville, in 1873. A comparison of the size of the present Courthouse and the Historic Old Courthouse in Knoxville is an indication of the rapid growth of Knox County during that period. From February 3, 1873, the actual date of the vacating of the Knoxville Courthouse, until January 11, 1887, when the Board of Supervisors first met in the present building, the old Opera House in Galesburg served as temporary quarters.