From an article by Brendan Scott published in Roots Ireland:

We are delighted to announce the addition of 579 Lease Abstracts for the Manor and Lordship of Monaghan (1679-1810) to the Roots Ireland database! These leases not only name the people who have agreed the lease, but also often mention other people and their properties in the leases and as such are a very useful census substitute for Monaghan.

For an up to date list of sources for Monaghan and to search these records, go to https://rootsireland.ie/monaghan and login or subscribe if required.

For more information about Roots Ireland, go to https://youtu.be/KG4VDiIq5gY.