South Armagh was a constituency of the Parliament of Northern Ireland.

It was created when the House of Commons (Method of Voting and Redistribution of Seats) Act (Northern Ireland) 1929 introduced first-past-the-post elections throughout Northern Ireland.

[citation needed] The seat was made up from parts of the rural districts of Armagh and Newry, especially Keady.

[1] The seat had a significant Nationalist majority, but Labour candidates were sometimes polled well.

[2] The remainder of contested elections involved candidates of different Nationalist persuasions.