Many thanks to David Best for bringing this to our attention. The following notice appeared in George Faulkner's Dublin Journal of 31 January, 1747:

From the 25th Day of March next, to be let a Farm of 60 Acres, or thereabouts, near Powerscourt in the County of Wicklow, within 10 (small) Miles of Dublin and two miles of Bray, in good sporting Country: There is a convenient dwelling House and several Out-Offices; two profitable Gardens one of them walled in with a large Tennis-Court. The Land is in good Heart, and there are discovered lately upon the premises rich valuable Marl Pits. The House is well situated to accommodate Lodgers who require Goats Whey, for the (Herbage) upon the Wicklow-mountains near Powerscourt is from well-try’d Experience, proved as medicinal and salutary as any upon the Mountains of (Moran). Whosoever pleases to treat for the same is desired to apply to Dr. Towers at his House in Henry-street, Dublin, or to enquire at the said Farm.

Text (in brackets) indicates an uncertain transcription; emphasis added.

Since the birth of lawn tennis occurred in the late 1800s, we can take the reference to a ‘Tennis-Court’ to mean a Real Tennis court. The IRTA would be very interested in hearing from anybody with any further information about this farm or its tennis court.