The United States Congress approved an enabling act on April 30, 1802, empowering the Ohio territory to begin the process of becoming a state. Thirty-five delegates were elected on November 1 to form a consitutional convention. Among them were Edward Tiffin, James Sargent, Francis Dunlavy, Bazaleel Wells, Nathaniel Massie, Thomas Worthington, Samuel Huntington, Ephraim Cutler, and Rufus Putnam. The delegates assembled in Chillicothe to write a constitution composed of sections from other state constitutions. This document was approved by Congress on February 10, 1803 and Ohio was admitted as the seventeenth state. The constitution is 19 pages and measures 9" x 14" (22.86 cm x 35.56 cm).

The 1802 Ohio constitution gave virtually all power to the legislature. The Senate and House of Representatives appointed the Supreme Court and the governor had no veto power. Although the constitution did ban slavery in Ohio, a motion to grant African Americans the right to vote failed by one vote in the constitutional convention.