The foundation stone for Peterswell/Kilthomas Church was laid on 9th October 1833 by Robert Blake Forster of Ashfield. The building was completed by Fr. O'Connor P.P. before he died in 1850, at the end of the Famine. The parish saw its population reduced from 3,066 inhabitants in the 1830s to 1,200 in the 1890s.
A belfry was added in 1880. In 1947-48 considerable renovations were carried out. The Fr. John Keely memorial stained glass window is by Evie Hone. The title is Our Lady of the Rosary.
Further improvements were made in 1973. A beautiful grotto of Our lady of Lourdes was added later. The church is dedicated to St. Thomas the Apostle. The parish has produced more than its share of priests.