Aghaviller (Irish: Áth an Bhiolair, meaning 'field of the watercress')[3] is the site of a church and round tower in County Kilkenny, Ireland.

[8] A few yards distant from the site of the old church, is the remains of the lower part of an ancient round tower composed of breccia.

[9] The Statistical Survey of 1802, makes reference to the tower,[fn 1] as does the 1855 Kilkenny Archaeological Society.

[fn 2] It is one of five round towers located around the county, the others are at Kilkenny, Tullaherin, Kilree and Grangefertagh.

[6] In 1851, the civil parish of Aghaviller contained the townlands of Aghaviller, Ballinteskin, Ballinva, Barnadown, Bartonsfarm, Boolyglass, Brownstown, Carrickmerlin, Castlemorris, Catstown, Coalpitparks, Condonstown, Croan, Hugginstown, Kingsmountain or Mylerstown, Kyleva, Mabbotstown, Mylerstown or Kingsmountain, Newmarket and Westmoreland.