County Antrim (Parliament of Ireland constituency)

County Antrim, Ireland, was represented in the Irish House of Commons by a county constituency of two knights of the shire (or MPs) until the abolition of the Irish Parliament on 1 January 1801. It was enfranchised as a parliamentary constituency at an uncertain date, between the first known meeting of the Parliament in 1264 and the division of the area into baronies in 1584.

The county was represented in the Parliament of the Commonwealth of England, Scotland and Ireland, under the Instrument of Government, after it was established in 1654 as part of the constituency of Down, Antrim and Armagh (constituency). Following the restoration of the monarchy in 1660 the Parliament of Ireland was re-established and the constituency again returned two Members of Parliament. In the Patriot Parliament of 1689 summoned by James II, County Antrim was represented with two members.

Under the Acts of Union 1800, it continued to be represented in the Westminster constituency of County Antrim with two MPs in the United Kingdom House of Commons.