County Westmeath is a former UK Parliament constituency in Ireland, returning two Members of Parliament from 1801 to 1885 and one from 1918 to 1922.
This constituency comprised County Westmeath, except for the parliamentary borough of Athlone 1801–1885.
Greville-Nugent was appointed a Groom in Waiting to Queen Victoria, requiring a by-election.
Pollard-Urquhart's death caused a by-election.
Gill resigned, causing a by-election.