The towns of Seaford and Blades are divided by the Nanticoke, historically a busy navigational waterway. The current bridge, replacing an older steel and timber swing span, is a lift structure of a type called “trunnion bascule,” the mobile “leaf' and its 305,000 pound concrete counterweight set in a pier below the bridge deck and rotating on a steel axle (the trunnion). The Chicago Bascule Bridge Company designed this fifty-five-foot span, built by Baltimore contractors. Chicago engineers also consulted on other Delaware bascule bridges of the 1920s—that first great era of highway construction—in Wilmington (S. Market St.), Newport, Milford, and Laurel.