The building appears on the 1842 Ordnance Survey map as "Newmarket Ho." and had been rechristened "Newmarket Court" by the time the 1904 edition was published, a small cartographic detail that hints at shifting ambitions or ownership, though the structure itself predates both maps by well over a century.

The house was built in 1713 by Richard Aldworth and is thought to have been designed by an English architect named Rothery. It is a two-storey building over a basement, with both its entrance front to the east and its view front to the south running to seven bays each. The southern elevation is the more decorative of the two, its central three-bay breakfront carrying superimposed pilasters, niches, and an entablature, the kind of formal classical layering common to early eighteenth-century Anglo-Irish architecture. The entrance front, by contrast, is more restrained, organised around a central pedimented doorway with a three-bay recess. The roofline that visitors see today is not original; the hipped roof was replaced in the 1950s, at which point the parapet wall and dormer windows were removed, altering the upper silhouette considerably. At some point between private residence and the twentieth century the house served as a convent before being restored in the 1980s as the O'Keeffe Institute. It now operates as a heritage centre and agricultural museum.