| County Down | |
|---|---|
| Former county constituency for the House of Commons | |
| County | County |
| 1801–1885 | |
| Seats | 2 |
| Created from | County Down (IHC) |
| Replaced by | East Down, North Down, South Down and West Down |
| 1922–1950 | |
| Seats | 2 |
| Created from | East Down, Mid Down, North Down, South Down and West Down |
| Replaced by | North Down and South Down |
County Down was a UK Parliament constituency in Ireland and later Northern Ireland. It was a two-member constituency and existed in two periods, 1801–1885 and 1922–1950.