Old Catonsville Historic District is a national historic district in Catonsville, Baltimore County, Maryland, United States. It was laid out with the construction of the electric railway and is overwhelmingly residential, with three churches (one with a school), a modern public library, and an Art Deco water tower. Architectural styles in the district range from mid- to late-19th century vernacular "I-houses" to late-19th and early-20th century styles such as Queen Anne, Bungalow, Colonial Revival, Dutch Colonial, Tudor Revival, and Craftsman. A large number of these dwellings have freestanding garages, typically finished in a like manner to their houses.

It was added to the National Register of Historic Places in 2002.

• Old Catonsville Historic District, Baltimore County, including photo dated 2004, at Maryland Historical Trust
• Boundary Map of the Old Catonsville Historic District, Baltimore County, at Maryland Historical Trust