Ohio elected its members October 13, 1818.
| District | Incumbent | This race | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Member | Party | First elected | Results | Candidates | |||||
| William Henry Harrison | Democratic-Republican | 1816 | Incumbent retired. New member elected. Democratic-Republican hold. | nowrap | √ Thomas R. Ross (Democratic-Republican) 48.7% John H. Platt 28.9% Ethan Stone 22.4% | ||||
| John W. Campbell | Democratic-Republican | 1816 | Incumbent re-elected. | nowrap | √ John W. Campbell (Democratic-Republican) 93.0% James Burin 7.0% | ||||
| Levi Barber | Democratic-Republican | 1816 | Incumbent lost re-election. New member elected. Democratic-Republican hold. | nowrap | √ Henry Brush (Democratic-Republican) 41.1% Levi Barber (Democratic-Republican) 30.3% Edward Tupper 28.6% | ||||
| Samuel Herrick | Democratic-Republican | 1816 | Incumbent re-elected. | nowrap | √ Samuel Herrick (Democratic-Republican) 52.9% John C. Wright (Federalist) 46.4% | ||||
| Philemon Beecher | Federalist | 1816 | Incumbent re-elected. | nowrap | √ Philemon Beecher (Federalist) 51.6% Joseph Vance (Democratic-Republican) 47.7% | ||||
| Peter Hitchcock | Democratic-Republican | 1816 | Incumbent lost re-election. New member elected. Democratic-Republican hold. | nowrap | √ John Sloane (Democratic-Republican) 51.7% Peter Hitchcock (Democratic-Republican) 46.2% Benjamin Martin 2.1% | ||||