Antrim (UK Parliament constituency)

County Antrim had been represented by two seats in the Irish House of Commons.

From 1801, under the Acts of Union 1800, it was represented by a county constituency with two MPs in the United Kingdom House of Commons.

It consisted of County Antrim, except the parts in the parliamentary borough constituencies of Belfast, Carrickfergus and Lisburn.

In 1885, Carrickfergus and Lisburn were disfranchised and the borders of the parliamentary borough of Belfast were extended.

In by-elections, to fill a single seat, the first past the post system applied.