County Monaghan is located in the Republic of Ireland in the province of Ulster. It is a border county and its natural hinterland includes counties Cavan, Louth and Meath in the Republic of Ireland, and Counties Fermanagh, Tyrone and Armagh in Northern Ireland.

The county capital, Monaghan town, is strategically located at the intersection of the N2 Dublin - Derry/Letterkenny and N54 National Routes, linking Dublin to the North-West and Belfast to the Midlands and Galway. The town is also located along a key east-west corridor linking Dundalk and Newry to Sligo and south Donegal. A new motorway from Derry to Clontibret is currently at route design stage.