Located close to the southwest border of the ancient Barony of Moycashel, Rosemount was once a stronghold of a prominent branch of the Geoghegan (Mag Eochagain) sept of the Southern UI Neill.

Like other Geoghegans in Moycashel, and wider Westmeath, they lost most of their prized grazing land and lake fisheries to the Cromwellian and Williamite settlers (both undertakers and officers) after the Down Survey.

In 1932 Harvard Archaeological Society excavated a Bronze Age cairn (cemetery) with the remains of 44 graves from the sixth century on top of Knockastia (or Cnoc Aiste), which at 200 m (656 ft) is one of the highest points in County Westmeath.

Rosemount and Grouse Lodge appeared on US entertainment show Access Hollywood in November 2006, featuring an on-site interview with Michael Jackson who spent five months there recording a new album.

As a rural club, development of young players has traditionally been important and this has resulted in a large number of successes in under-age finals, particularly in the 1970s.