Founded in 1864, Immaculate Conception was the first mission church of Saint Patrick’s, organized to serve the Roman Catholic population in the then-sparsely settled area north of Mount Vernon Square. Immaculate Conception’s establishment reflects the growth of the Irish immigrant population in DC and presages the rapid postwar expansion of the city north of Massachusetts Avenue. Additionally, it is associated with notable pastors such as its founder, Rev. J. Walter, who was the confessor and defender of Mary Surratt, the woman put to death on co-conspirator charges after Lincoln’s assassination.
When the original church building was constructed between 1864 and 1865, it was surrounded by only a few buildings along dirt roads, and cows wandered the streets. With the construction of the O Street Market and the Seventh Street streetcar line, however, the area lost some of its former "Cow Town" feel and gradually became more developed. The new Immaculate Conception Church, built between 1870 and 1874 to accommodate the growing congregation, became part of an urban community.
After much of this area was destroyed during the events of 1968, Monsignor Joshua Mundell of Immaculate Conception worked to stabilize the neighborhood, encouraging church and federal government collaborations to build modern, affordable housing, including the Immaculate Conception Apartments.
DC Inventory: July 24, 1968 (Joint Committee on Landmarks)
Nomination expanded on November 21, 2002 to include school, rectory, and residence
National Register: September 17, 2003