Holy Cross Chapel can be found in the Parish Ministries Building. This building was built in 1928 as the convent for the Sisters of St. Dominic who staffed both the St. Agnes Elementary School and High School.
In 2000 the convent, no longer needed by the nuns of the parish who had found alternate housing, underwent a major renovation.
As part of this renovation, which converted the first two floors for use by the many parish ministries, the chapel was restored to its original grandeur. The chapel was renamed the Chapel of the Holy Cross in honor of the Amityville Sisters of St. Dominic, Congregation of the Holy Cross.
Although small in size, with seating for approximately 50 people, it is a gem within the cathedral complex. Today it is used for Eucharistic Adoration, special masses and prayer services.