Old St. Mary's Church (Cincinnati, Ohio)

Old St. Mary's Church, School and Rectory
Front of the church with its tower
Location123 E. 13th St., Cincinnati, Ohio
Coordinates39°06′34″N 84°30′45″W / 39.10944°N 84.51250°W / 39.10944; -84.51250
Area1.9 acres (0.77 ha)
Built1841
ArchitectFranz Ignatz Erd
Architectural styleGreek Revival, Late Victorian
Part ofOver-the-Rhine Historic District (ID83001985)
NRHP reference No.76001439
Added to NRHPMarch 13, 1976

Old St. Mary's Church is a Roman Catholic church in Cincinnati's historic Over-The-Rhine neighborhood. It is the oldest continually-used house of worship in Cincinnati.

Old St. Mary's is the oldest church in Cincinnati, and since 2017, home to The Cincinnati Oratory, a society of priests and brothers of The Congregation of the Oratory of St. Philip Neri. The church was organized in 1840 by German immigrants, at a time of dramatic growth in the city's population.

Designed in the Greek Revival style by Franz Ignatz Erd, it is the second-oldest German-Catholic parish in the city and the oldest standing church in Cincinnati. The church is 142 feet long, 66 feet wide and with a steeple 170 feet tall. When built, it was the largest church in the Ohio Valley. The original church was dedicated on July 3, 1842.