Thomastown, historically known as Grennan, is a town in County Kilkenny in the province of Leinster in the south-east of Ireland. It is a market town along a stretch of the River Nore which is known for its salmon and trout, with a number of historical landmarks in the vicinity. Visitor attractions include Jerpoint Abbey, Kilfane Glen gardens, and Mount Juliet Golf …Thomastown, historically known as Grennan, is a town in County Kilkenny in the province of Leinster in the south-east of Ireland. It is a market town along a stretch of the River Nore which is known for its salmon and trout, with a number of historical landmarks in the vicinity. Visitor attractions include Jerpoint Abbey, Kilfane Glen gardens, and Mount Juliet Golf Course. The town is in a civil parish of the same name. As of the 2022 census, Thomastown had a population of 2,305, making the town the third most populous in the county.