Claremorris ( Irish: Clár Chlainne Mhuiris) is a town in County Mayo in the west of Ireland, at the junction of the N17 and the N60 national routes. It is the fastest growing town in the county. There was a 31% increase in the town's population between 2006 and 2011 and a 23% increase between 2002 and 2006. The population of Claremorris in the 2016 Census was 3,687, rising from 3,412 in the 2011 Census.
The town sits at the bottom of a valley, all roads leading to the town follow hills, in particular the old Knock road (known as the Knock hill) and Courthouse road. Although low-lying, the town does not experience flooding. There is no major river through the town although there are two lakes in the town centre: Clare Lough where the 'Land of the Giants' amenity is located and Mayfield Lough. A small river flows between the two.
The town derived its name from Maurice de Prendergast, a Norman who came to Ireland in 1169.
The town was established during the 18th century. In 1822 the Roman Catholic Chapel was built, which was later demolished to make way for the town hall. The present Roman Catholic Church St Colman's Church, was built in 1911. St. John's Anglican Church, now the town library, was built in 1828.
The main landlord family in Claremorris was the Browne family, one of whom, the Hon. Denis Browne (1760-1828), was High Sheriff of Mayo during the Irish Rebellion of.1798 and acquired the nickname of "Donnchadha an Ropa" (Denis the Rope) as a result of his treatment of captured Irish patriots.
At the 2016 Census, Claremorris had a total population of 3,687 people, consisting of 1,720 males and 1,967 females. 24.3% percent of the population were non-Irish nationals and 89.7% of the resident population had lived at the same address as for the year before. Catholics constituted 82.9% of the population.
Genealogical records for Claremorris consist of Roman Catholic church records of marriage which commenced in 1805 and baptisms which commenced in 1825. Church of Ireland records consist of baptisms from 1834 onwards, marriages from 1846 onwards and burials from 1878 onwards. These are held at the South Mayo Family Research Centre in Ballinrobe.