John Elfreth Watkins Sr. (1852–1903) was Curator of Mechanical Technology at the United States National Museum (Smithsonian Institution). He received his education at Lafayette College, graduating in 1871, and worked first for the Delaware & Hudson Canal Company, as a mining engineer, for a year, and then for the Pennsylvania Railroad as assistant engineer of construction. Disabled in 1873 by an accident that resulted in the loss of his right let, he was reassigned to the Amboy division of the railroad. In 1883 h became chief clerk of the Camden and Atlantic Railroad and in 1884 chief clerk of the Amboy division of the Pennsylvania Railroad.
In that same year, he became Honorary Curator of Transportation at the National Museum, taking the job full-time after two years. He left to organize the Pennsylvania Railroad's exhibits at the 1893 World's Columbian Exposition; stayed in Chicago for a year organizing the Department of Industrial Arts at the Field Columbian Museum; and then returned to the Smithsonian, where he was curator of Mechanical Technology until his death in 1903.