In 1843 and 1844 Rev. Father Yilanus, D.D., of St. John's College, Fordham, attended New Rochelle once a month; also- Sawpits, Westchester, Throgg's Point and Sing Sing. In 1845, Rev. William O'Reilly, of Westchester, had chai'ge of these missions. In 1846 and 1847, Rev. Matthew Higgins, of Westchester, attended New Rochelle and Port Chester. In 1848, Rev. Valeuive Burgos resided in Port Chester, and was succeeded towards the end of 1848 by Rev. Edward J. O'Reilly.

Father O'Reilly was the first Catholic priest to conduct services in White Plains. He began to hold meetings there about the year 1848. At this time he had charge of the Roman Catholic mission in Port Chester. In 1849 or the early part of 1850 he removed to New Rochelle, having been appointed pastor of St. Matthew's Church, at that place, in addition to his Port Chester charge.

Father O'Reilly was a zealous worker for the advancement of the Roman Catholic faith, and a man of more than ordinary ability and force of character. For several years after the beginning of his ministrations in White Plains, the Catholics there were without a house of worship of their own. Father O'Reilly, anxious to supply this need, solicited subscription& from Catholics and Protestants, and was finally able to effect his wish. A plot of ground, located where Hamilton Avenue and SpringStreet afterwards crossed each other, was purchased in the latter part of 1852,. and shortly afterward the church was erected.

Father O'Reilly was succeeded by the Rev. Thonia* McLoughlin, of New Rochelle. From 1848 to 1860 White Plains was visited once a month from New Rochelle. From 1861 to 1868 it was attended by the Rev. Matthew Dowling, of Port Chester, Port Chester having been made a separate mission in 1855.