In addition to Holy Trinity Church and Holy Trinity Catholic school, the parish operated the former St. Ann Chapel in Wilpen beginning in 1913. A former coal company town about five miles outside of Ligonier, Wilpen once boasted a population greater than that of Ligonier borough.

Long working hours, a scarcity of transportation, and a 10 mile walking distance prevented Wilpen residents from attending Mass in Ligonier. Bishop Regis Canevin from Pittsburgh then granted permission to celebrate Mass in an old schoolhouse in Wilpen. The first Mass in the coal company town was celebrated in a schoolhouse on Christmas Day 1908. Thereafter, priests from Saint Vincent Abbey celebrated Mass on the first Sunday of each month.

A year later, fire destroyed the school and the worship site was moved to a hall near the company store. It wasn't long before parishioners petitioned for the building of a chapel in Wilpen. In 1911, Benedictine Father Felix Fellner (pastor of Holy Trinity Parish from 1902-21) requested assistance from the vice president of Shenango Furnance for construction of a church. A company gave a $500 monetary contribution and a site for the building. Unfortunately, because of the heat from the nearby coke ovens, the site was deemed unsafe.

At Father Felix's request, the Seger Company contributed two lots, and land was offered on which a foundation had already been laid. A building contract was awarded to Lohr of Ligonier, and a cornerstone for St. Ann was laid June 22, 1913. The service was conducted by Archabbot Leander Schneer. The chapel was completed and blessed as St. Ann, a mission from Holy Trinity Parish, in November 1913.

The Wilpen mission continued to have the greatest census until the end of the Second World War when mining began to decline. Meanwhile, the town of Ligonier was experiencing a slow and continuing growth as families from Pittsburgh built summer homes away from the noise and pollution of the industry. Census figures eventualy favored Holy Trinity Parish.

The chapel underwent extensive renovations from 1927 top 1934. Further renewal was accomplished over a nine-year period beginning in 1956. St. Ann celebrated its Golden Anniversary with Bishop William G. Connare, the second bishop of Greensburg, in 1963. The chapel went on to celebrate its 75th anniversary in 1988 and its 90th in 2003. The chapel closed its doors January 2, 2008.