The Presbyterian Church in Birr grew in numbers in the 1840s following the Crotty Schism. Fr William Crotty (with his cousin Fr Michael Crotty) led this breakaway Catholic congregation to join the Presbyterian Church. Crotty's Church built to emulate a Presbyterian Hall was erected in Castle Street in 1839. A new church building for the Presbyterian congregation was erected in 1885 in John's Mall, not now in use.