St. Mary's Cathedral is a Catholic cathedral located in Ogdensburg, New York, United States. It is the seat of the Diocese of Ogdensburg. St. Mary's parish was founded in 1827. The original St. Mary's Cathedral was located at Montgomery and Franklin Streets. The cornerstone was laid in 1855 and it was destroyed in a fire on November 25, 1947. The current cathedral was completed in 1952 and consecrated on October 22 of that year.