Early voting for the special election will be available through Aug. 6 at the Butler County Board of Elections, 1802 Princeton Road, Suite 600.
If approved, the measure on the ballot would make it harder for Ohio voters to make changes to the state constitution. It would require a 60% supermajority of Ohio voters to amend the constitution, rather than the presently required 50% plus one.
Voting hours in person at the Board of Elections will be from 8 a.m. to 5 p.m. from July 24 to July 28.
In-person voting from July 31 to Aug. 6 will be from 7:30 a.m. to 7:30 p.m. Monday, Wednesday, Thursday and Friday; 7:30 a.m. to 8:30 p.m. Tuesday; 8 a.m. to 4 p.m. Saturday; and 1 to 5 p.m. Sunday.