Illinois's Second State Constitution, which was adopted in 1848, provided for one Supreme Court divided into three Grand Divisions. Mt. Vernon was designated as the site of the First Grand Division, Springfield was the site of the Second Grand Division, and Ottawa was the site of the Third Grand Division. In 1854, the state legislature appropriated $6,000 for the erection of the Supreme Courthouse for the First Grand Division in Mt. Vernon. The courthouse was built here on property donated by Zadok Casey, the founder of Mt. Vernon and a former Lieutenant Governor of Illinois. In 1857, the courthouse was completed.