Most of Pier 70 is listed on the National Register as the Union Iron Works Historic District and is considered one of the most intact industrial complex west of the Mississippi. Home to headquarters for both Union Iron Works and Bethlehem Steel, Pier 70 was home to ship repair operations from the time of the Spanish American War in 1898 through today. In particular, Pier 70 is notable for its role in the nation’s maritime history, supporting multiple war efforts, as well as in the evolution of industrial architecture in San Francisco. The Historic District contains many contributing resources, including buildings, piers, slips, cranes, segments of a railroad network, and landscape elements. Most of the buildings are of an industrial architectural style and historic use, and made of unreinforced brick masonry, concrete, and steel framing, with corrugated iron or steel cladding.
The Historic District is characterized by the following features:
• Waterfront location;
• Numerous contributing features dating from 1884 to 1945;
• Minimal planted vegetation;
• Open areas that are paved or covered with gravel;
• Streets without curbs or gutters (except for 20th Street, which has granite curbs);
• Dense urban industrial character;
• Buildings that vary in scale, from 60,000 to 100,000 square feet and heights from one to six stories (80 feet), as well as a wide range of architectural treatments and materials;
• Unique groupings of buildings, including the unreinforced monumental masonry Buildings 113 and 114, as well as the steel-frame and corrugated-metal World War II Building 12 complex;
• Wharves, piers, slips, cranes and floating drydocks; and
• Ongoing ship repair activity