The Northern Ireland Assembly has 90 members, elected in 18 five-member constituencies by the single transferable vote (STV) method.
[1] Northern Ireland is represented at Westminster by 18 single-member constituencies elected by the first-past-the-post method.
From 1979 to 2020, three of the seats in the European Parliament allocated to the United Kingdom formed a three-seat constituency elected by single transferable vote.
It differed from European Parliament constituencies elsewhere in the United Kingdom which used the D'Hondt method.
The United Kingdom withdrew from the European Union on 31 January 2020, and the constituency was abolished.