Convention: In Law, A body constituted by statute to represent the people in their primary relations, and in some sense outside of the constitution, as e.g. for the framing or amending of the constitution itself (Constitutional Convention). In this sense, applied to a body meeting under authority of Congress to frame a constitution for a new state, or convened by a state legislature, in the manner prescribed by law, to revise the constitution of the state.
Oxford English Dictionary
Many states during this time period continued to either create (for new states) or refine their state constitutions. This resulted in numerous elections for convention delegates.
1787 - 1824: Alabama, Connecticut, Delaware, Georgia, Illinois, Indiana, Kentucky, Louisiana, Maine, Maryland, Massachusetts, Missouri, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Vermont, Virginia
Office Scope: State / Territory
Role Scope: State / County / District / City