Walter H. Gahagan (ca. 1869-1931) was an engineer and general contractor who owned a construction business based in Brooklyn, New York, and a shipyard in Arverne, Queens. Among other projects, his firm worked on the Lackawanna Cut-Off, an immense railroad project in northwestern New Jersey.
Born in Ohio, Gahagan married Lillian Rose Mussen, a schoolteacher who had grown up in Wisconsin. In 1897, they moved to Brooklyn and soon had twin boys, Frederick and William. In the summer of 1900, the family moved temporarily to Boonton, New Jersey, where Gahagan's company was building a reservoir. Their daughter, Helen, was born on November 20, just before the family moved back to Brooklyn. In 1902, another daughter, Lillian, was born, and the family moved to a large brownstone house at 231 Lincoln Place in Brooklyn's Park Slope neighborhood. In 1910, their last child, Walter Jr., was born. In 1914, Gahagan bought a vacation home in Fairlee, Vermont, and the family thereafter spent parts of each summer there. In 1931, the year Gahagan died, the family was living at 17 Prospect Park West.
Helen Gahagan Douglas became an actress and a pioneering politician who served as a three-term U.S. Congresswoman from California and who lost the 1950 race for U.S. Senate to Richard Nixon. Walter Jr. graduated from Princeton University in 1932 and Columbia University law school in 1935, competed in discus and exhibition football at the 1932 Summer Olympics in Los Angeles, then took over the family business, which subsequently helped build the launching pad for the Apollo space missions and Kennedy and Newark airports.
Gahagan founded his contracting business in 1899 and by 1924 owned two companies, W.H. Gahagan, Inc., and Gahagan Dredging, Inc., which employed between 100 and 4,000 people, depending on contracts, and which owned and operated dredges, steam shovels, and at least 10 steam locomotives. Between 1908 and 1911, Gahagan's firm was one of seven contractors who built the Lackawanna Cut-Off.
In 1918, Gahagan built a shipyard on Jamaica Bay on a plot of land measuring 600 by 2,000 feet. The facilities included a sawmill measuring 600 by 200 feet, various auxiliary shops, 1,000 feet of launching ways, and 1.5 miles of rail siding that was laid by the Long Island Rail Road. A news report published before the yard's opening said that construction would take 30 days, that the yard would employ about 250 people, and that its first contract was a U.S. government order for 30 barges of 100 feet in length and 32 feet abeam. Among the other work done by the Averne shipyard was the construction of a 10,000-ton floating wooden drydock for $800,000 for the Emergency Fleet Corporation.