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Maryland's National Register Properties

Photo credit: Pamela M. James, 09/1975
Patterson Viaduct Ruins
Inventory No.: BA-1850, HO-63
Other Name(s): Ilchester Bridge
Date Listed: 6/3/1976
Location: Ilchester Road & River Road, Catonsville, Baltimore County, Howard County
Category: Structure
Period/Date of Construction: 1829
Architect/Builder: Designer: Caspar Wever; Builder: John McCartney
Description: The remains of the Patterson Viaduct stand on the east (Baltimore County) and west (Howard County) banks of the Patapsco River just south of the present bridge carrying the Baltimore and Ohio Railroad over the river near Ilchester, Maryland. The bridge rose about 43' above its foundations. It had four graduated arches--two of 55' chord each and two of 20' chord each. The smaller arches were introduced for the accommodation of two county roadways, one on each side of the river. The viaduct, constructed of granite blocks, was approximately 360' in length. The exterior surfaces of the granite blocks were undressed, or rusticated. The viaduct was almost totally destroyed in the great Patapsco Valley flood of 1868. A single-span Bollman truss built into the west abutment in 1869 incorporated the original roadway arch and upstream wingwall. With the realignment of the railroad 400' upstream in 1902-03, the Bollman bridge was left unused. Today, all that remains at the original crossing is the single masonry roadway arch of the 1829 construction on the west bank and the stone abutment on the east bank. Significance: The Patterson Viaduct, built from May to December of 1829, was part of the original main line of the Baltimore and Ohio Railroad. It was constructed in the first building phase of the railroad, which extended from Baltimore City to Ellicott's Mills. The Patterson, the third bridge built for the B & O, is similar in construction to the Carrollton Viaduct in Baltimore City. Designed by Caspar Wever, it was built under the supervision of John McCartney, one of his assistants. McCartney received the contract to build the Thomas Viaduct as a result of his successful completion of the Patterson contract.


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