The design for the town was commissioned in the 1780s by the John Browne of the nearby stately home, Westport House, as a place for his workers and tenants to live. John Browne cleared the original village of Cahernamart, that had 700 inhabitants, to make way for his gardens at Westport House.
The current town centre was originally designed by James Wyatt in 1780, in the Georgian architectural style. Its layout follows the medieval principles of urban design introduced by the Normans in the 13th century. A particular feature is the incorporation of the river into the composition, contained for two blocks by low stone walls producing, on each side of the river, tree lined promenades (The Mall) with several stone bridges over the river Carrow Beg. The layout further includes several tree lined streets, addressed by the narrow fronted commercial buildings typical of Irish towns, though with many here remaining of a singular refinement and charm. Some modern interventions, such as the Garda station, are less successful in maintaining the original continuity of the urban fabric.
The famous pilgrimage mountain of Croagh Patrick, known locally as "the Reek", lies some 10 km west of the town near the villages of Murrisk and Lecanvey. The mountain forms the backdrop to the town.
Westport is a popular tourist destination and scores highly for Quality of Life. It has also won the Irish Tidy Towns Competition three times in 2001, 2006 and 2008; in 2012 it also won the Best Place to Live in Ireland competition run by The Irish Times.