The formal title is Church of St. Mary, Our Lady of the Isle Construction of the church began in 1896 and was completed in July 1897. The first Mass was celebrated on August 8, 1897

The dimensions of the church have not changed substantially in the past century: 44' wide by 82' in length including a 14' square, two story tower with no bell. The church, including the choir, seats 350 people.

Interesting features of the church include: The stained-glass windows, installed in 1922 as memorials to various parishioners; the beautiful statue of Our Lady of the Isle in front of the church, sculpted in Italian marble by DePrato and donated by parishioners in 1956; the statue of the Crucifixion, restored and mounted on the wall in 1999, with the cross erected in he basement, both purchased by Fr. Griffin in 1916.

Major renovations to the interior of the church, to conform to the liturgical emphasis of Vatican II, were completed during the tenure of Fr. Daniel Carey. At the same time an entrance on Cambridge Street was built for safety and convenience and now provides elevator and handicapped access to the church.

The entire church was renovated from 1997 to 2000 at a cost of approximately two million dollars. A new organ was ordered from M.L. Bigelow Company of Utah to be installed later. At the rear of the church were installed two new stained-glass windows honoring Monsignor Lester C. Hull, former pastor, who died in 1982, and Albert F. "Bud" Egan, parish benefactor, who died in 2000.

Main entrance doors of polished teak were installed in 2000 to conform the entry with the renovated interior of the church. The previous doors, a gift in memory of Virginia Vaughan, were mounted in the lower level.

The new pipe organ was installed in the choir loft in 2001 under Fr. Paul Caron who also installed a new sound system to the church in 2006. In addition a cupola was placed on the church in 2003 so that the Carrillions could call people to worship, Ring the Angelus, and play hymns, as well as Toll at a funeral, or peal at a wedding.

The church doors are open to all people, every day of the year, to provide a shrine and refuge in the heart of Nantucket Town.