1857 General Election - Portarlington
| Year | 1857 |
| General election | 1857 General Election |
| Constituency | Portarlington |
| Turnout | 83.9% |
Results
| Candidate | Party | Votes |
| Dawson-Damer, Lionel Seymour William | Conservative | 42 |
| Dunne, Francis Plunkett | Conservative | 36 |