The Delaware River Iron Ship Building and Engine Works (founded in 1871), was a major late–19th-century American shipyard located on the Delaware River in Chester, Pennsylvania. It was founded by the industrialist John Roach and is often referred to by its parent company name of John Roach & Sons, or just known as the Roach shipyard. For the first fifteen years of its existence, the shipyard was by far the largest and most productive in the United States, building more tonnage of ships than its next two major competitors combined, in addition to being the U.S. Navy's largest contractor.