| Old Catonsville High School | |
| Location: | 20 Winters Ln., Catonsville, Maryland |
| Coordinates: | 39.2728°N -76.736°W |
| Built: | 1878 |
| Architect: | Davis, Henry R. |
| Added: | September 10, 1987 |
| Refnum: | 87001568 |
Old Catonsville High School, also known as St. Mark's School, is a historic school building located at Catonsville, Baltimore County, Maryland. It is a masonry schoolhouse which consists of a one-story, single bay structure (built in 1878) and a three-story, four bay addition (built in 1898). In 1885 the school was designated a high school and in 1910 the property was sold to the Catholic Church.[1]
It was listed on the National Register of Historic Places in 1987.