Athlone (Gaelic: Átha Luain) is a town in Ireland on Earth. It sits in the rough geographic center of the island, straddling the River Shannon, on the border between the counties of Westmeath and Roscommon. The town's castle was considered a minor tourist attraction, and the All-Ireland Drama Festival was held there annually. The town was also home to Sean's Bar, known to be the oldest pub in the British and Irish Isles, having operated continuously from the year 900 AD into the 24th century.
Though born in Belfast, Mark Montgomery lived with his family in Athlone, and grew up there before moving to the Aldebaran colony in his teens. While staying on Earth, Mark's parents, Ambassador Dominic Montgomery and Carol Montgomery lived in Athlone. Timothy Sinclair would often visit the Montgomerys during his retirement from Starfleet, and often said Sean's was his favorite pub. (Star Trek: Pendragon)