The objectives of Manorhamilton Historical Society are to promote interest in the history, heritage and archaeology of Manorhamilton and its surrounding area. The town itself is now nearing the 400th anniversary of its founding by Sir Frederick Hamilton whose castle was built here between 1634 and 1636. Major historical events and their impact on area are commemorated by the society through lectures, exhibitions and outings.
The lives of North Leitrim men lost in WW1 was the theme in 2014. A fitting tribute was paid to Proclamation Signatory Sean Mac Diarmada by the renaming of a street in his memory in 2016. The widespread benefits which the Sligo, Leitrim & Northern Counties Railway brought to the region were recalled in 2017 when the Society mounted a photographic and memorabilia exhibition to mark sixty years since the closing of the line.