Seven Foot Knoll Lighthouse, Mouth of Patapsco River, Riviera Beach, Anne Arundel County, MD

Significance: Built in 1856, the Seven-Foot Knoll Lighthouse was the second screwpile structure built by the U.S. Lighthouse Service. The present structure contains some elements of the original cast-iron structure, and the house dates from the late 19th Century. The light is historically linked to the development of the Port of Baltimore and sits beside one of the busiest shipping lanes on the East Coast. Technologically, the screwpile form illustrates Americans' ability to produce large cast-iron foundry castings, the same development that produced cast-iron architecture. In the period 1835-1860, Baltimore was a leading national center of this new metal-working technology and of new marine engineering techniques. Seven-Foot Knoll is, arguably, the most significant of the remaining screwpile structures.
Survey number: HAER MD-54
Building/structure dates: 1856 Initial Construction
Building/structure dates: 1910 Subsequent Work