The development of the St. Mary's property began in 1695 with the purchase of land for a burying ground on the west side of Wood Street. In 1702, another lot between the original lot and Broad Street was purchased for the erection of a church, and construction began on Old St. Mary's Church, the first purpose-built house of worship for a Church of England congregation in New Jersey. The cornerstone was laid in March 1703, and the building was completed in 1705. As the congregation grew, the original meeting-house form was enlarged in 1769 in both length and width, possibly to a design by Philadelphia builder and architect Robert Smith. After the Colony's Declaration of Independence in 1776, the church was closed because of its association with the Church of England, and it remained closed until 1784, when it resumed activity as part of the newly formed Protestant Episcopal Church in the United States of America. As the church recovered and grew after the Revolutionary War, its interior was altered in 1810-1811 and an apse for a new chancel was added on the eastern end according to a design by architect Robert Mills. In 1834-35, it was enlarged again with new sections on the north and south sides forming the transept and crossing and new sections forming the nave and sacristy, with the new south exterior front designed in the Greek Revival style by architect Isaac Holden. In 1847, while New St. Mary's Church was under construction, galleries were added in the west transept and north end of the nave to accommodate the increasing congregation. After New St. Mary's Church was completed in 1854, the old church was no longer needed for regular worship services. In 1875, the interior was altered so that the earlier sections of the building became a Sunday School room, the north 1834 addition became a Parish School room, and the south addition became a Bible classroom and Parish library. This work stripped away walls and ceilings, replaced the roof and roof structure, and installed entirely new structure and finishes, including a partition wall between the new Parish and Sunday School rooms, to a design by architect William D. Hewitt. The building underwent a comprehensive restoration in 1999-2000, and today Old St. Mary's Church is one of the oldest extant churches in New Jersey.