In the first Parliament to be held after the Union of Great Britain and Ireland on 1 January 1801, the first House of Commons of the United Kingdom was composed of all 558 members of the former Parliament of Great Britain and 100 of the members of the House of Commons of Ireland.
The Parliament of Great Britain had held its last general election in 1796 and last met on 5 November 1800. The final general election for the Parliament of Ireland had taken place in 1797, although by-elections had continued to take place until 1800.
