The Basilica of the Immaculate Conception is a Roman Catholic church located at 74 West Main Street in Waterbury, Connecticut.

On his first arrival, Smyth thought to say Mass in the same house frequented by McDermot but was told be the tenant that the landlord had threatened eviction if he entertained anymore priests.

In 1845, Washington Hall, on the corner of Exchange Place and West Main Street was rented from Dr. Jesse Porter.

[3] In 1847, the Catholic community purchased a former Episcopal church and sought to move it to a lot on the corner of East Main and Dublin Streets.

However, on approaching the desired location, the contractor, Major D. Hill of Hartford, was convinced that he could not get the structure safely over the high ground, so Neville, acting as agent for the Catholics, purchased a second, more accessible lot.

Bishop Tyler of Hartford purchased a lot south of Grand Street through John Galvin for use as a burying ground.

Initially O'Neil resided with the family of Michael Neville, on Dublin Street opposite the cemetery gate.

It was dedicated by Bishop McFarland, and renamed in honor of the Immaculate Conception, the first church in the United States to bear that title since the 1854 decree.

The instrument was built in 1928 and has received modifications over the years including a new console in 1970 and some restoration work by the Foley Baker Company in 1980.