Constituencies of the Irish House of Commons

The Irish House of Commons had 150 constituencies prior to the abolition of the Irish Parliament on 1 January 1801 under the Acts of Union 1800. Each elected two members of parliament to give a total of 300 MPs.

The number of boroughs invited to return members had originally been small (only 55 boroughs existed in 1603) but was doubled by the Stuart monarchs. By the time of the Union, there were 150 constituencies, each electing two members by plurality block voting; an elector could vote for one or two of the candidates, with the two receiving most votes being returned. The constituencies had different franchises as follows:^[1]

• 32 county constituencies;
• 8 county borough constituencies;
• 109 borough constituencies, of varying franchises:
• 1 university constituency (Dublin University).

Following the Act of Union, from 1801, there were 100 MPs from Ireland in the House of Commons of the United Kingdom. The Irish constituencies at Westminster were a subset of those in the Irish House of Commons as follows:

• the 32 counties and two most populous county borough constituencies, Cork City and Dublin City, retained two MPs each;
• the 6 other county boroughs, the university, and the 25 most populous boroughs were reduced to one MP each;
• the 84 least populous Irish parliamentary boroughs were disfranchised after the Union.