Cavan–Monaghan is a parliamentary constituency represented in Dáil Éireann, the lower house of the Irish parliament or Oireachtas. The constituency elects five deputies (Teachtaí Dála, commonly known as TDs) on the system of proportional representation by means of the single transferable vote (PR-STV).

It was created under the Electoral (Amendment) Act 1974 and was first used at the 1977 general election.^[1]

The constituency includes the entire area of both County Cavan and County Monaghan, taking in Cavan town, Monaghan town, Clones, Cootehill, Belturbet, Bailieborough, Castleblayney and Carrickmacross. It also include as small portion of territory from County Meath.^[2]

At the 2016 general election, 36 electoral divisions in the west of County Cavan were transferred to the Sligo–Leitrim constituency and Cavan–Monaghan became a 4-seat constituency.^[3] This was reversed by the Electoral (Amendment) (Dáil Constituencies) Act 2017, which took effect at the 2020 general election.

The Constituency Review Report 2023 of the Electoral Commission recommended that at the next general election, Cavan–Monaghan remain as a five-seat constituency, consisting of the whole of the counties of Cavan and Monaghan, with the area in the north of County Meath transferred to Meath East.^[4]

For the next general election, the Electoral (Amendment) Act 2023 defines the constituency as:^[5]

"The county of Cavan and the county of Monaghan."

Cavan–Monaghan is predominantly rural with 75% of the population living outside the main towns. Manufacturing, construction and agriculture are the largest sectors of the local economy.^[14] In the 2000s there was an influx of people moving to south-east Cavan from Dublin, benefiting from the low house prices and good transport links to the capital.

Due to its proximity to the border the constituency has historically been strongly Republican; hunger striker Kieran Doherty won a seat in the 1981 general election as an Anti H-Block candidate. In recent elections, the constituency has seen mainly a three-way fight between Fine Gael, Sinn Féin and Fianna Fáil, with the Labour Party traditionally polling poorly.

Note: The columns in this table are used only for presentational purposes, and no significance should be attached to the order of columns. For details of the order in which seats were won at each election, see the detailed results of that election.

• Elections in the Republic of Ireland
• Politics of the Republic of Ireland
• List of Dáil by-elections
• List of political parties in the Republic of Ireland