The early Sing Sing community of Catholics began to grow significantly during the construction of the New York City Water System in 1837. It took four and one-half years to build the Double Arch (located at Aqueduct Street, Ossining) and as a result many Irish immigrants involved in its construction settled in Sing Sing, as Ossining was once known.

In Verplanck, in 1843, St. Patrick's Church became the center of the missionary effort to outlying areas. Sing Sing was one of these areas.

During those early years, Mass was celebrated at various sites throughout the village: John and Bridget O'Brien's home at the junction of North Highland Avenue and Cedar Lane was the site of the first Mass of the defined parish. Also used were: the brick structure on the south side of Emwilton Place, formerly a Reform Dutch Church; the Franklin Academy (later St. Paul's Rectory on St. Paul's Place); Vance's Hall where the Starling Building stood on the southeast corner of Main and Spring Streets; and a storehouse on the dock of the Porous Plaster Company, which Dr. Benjamin Brandreth, then the President of the Village of Sing Sing, provided to the Parish rent free. It was not uncommon for Sing Sing Catholics to walk the ten miles to St. Patrick's in Verplanck for Sunday Mass.

Thus the need for a church grew and out of that growth the parish of St. Augustine was born. On October 24, 1853 Property within the village limits was purchased from "Francis Larkin, wife and others." This property was located on the west side of the Highland Turnpike, the present North Highland Avenue. The price for the 100' by 125' lot was $450.00. From 1853 to 1862 several other lots were purchased, and these lots became the grounds of the original St. Augustine Parish. Plot by plot, over the years, the land on which the old church, the rectory, the convent and the garage were built, was bought, each part a testimonial to the effort of Pastor and people. Unfortunately, there is no record indicating why St. Augustine was chosen as our parish patron saint, and even less is known about the details of building the church.

We do know, according to information furnished by the parents of the late Mrs. John V. Kirby and the late Frank Keenen, that "the O'Brien Brickyards of Verplanck donated the bricks with the provision that should “any of the owner's descendants ever need money, the church would pay the full value of the bricks." Thus, the red brick was delivered and the little church was constructed up to the side doors...and as parishioners tell: "a later generation paid for the bricks."

Five years from the date of purchase the local paper. "The Republican," in its November 15, 1858 issue, published this illuminating account of the St. Augustine dedication:

"In accordance with the announcement previously made in this Journal, St. Augustine's R. C. Church was dedicated to Divine Worship, on Sunday Morning last, the dedicatory ceremonies being performed by Archbishop Hughes.

After the ceremonies of dedication had been concluded the Archbishop, although, in feeble health, delivered a short and eloquent address appropriate to the occasion and congratulated the people upon the successful completion of so handsome a church edifice. High Mass was celebrated, after the formulas of the Church, and was witnessed by many of our citizens as well as those belonging to Church..."

Finally, on August 28, 1878 Cardinal John McCloskey had all the parcels of land transferred to St. Augustine. Thus St. Augustine became a regular incorporated parish.

Two points of interest were the burials on the church grounds of Father McGean and Father McClellan, Father Edward McGean, whose monument was south of the church, had been Pastor from 1856 until his sudden death from heart disease in 1861.

During that time, the vestry and chancel were added to the church, Father William McClellan followed in 1861 until his death from apoplexy in 1871. He was buried in a plot north of the church, the last interment on the grounds. Father McClellan was instrumental in building the new rectory during his incumbency. (The remains of Father McGean and Father McClellan were transferred to St. Augustine Cemetery prior to the parish move to Eagle Park).