This pencil-drawn site plan was produced by the City and County of San Francisco’s Department of Public Works, for the Mills Field Municipal Airport of San Francisco, titled “Progress Chart for Grading / Contract No. 1” and dated March 18, 1927. Keen eyes will spot the three proposed runway locations and lengths, as well as the administrative building and hangar. The City’s Engineer, Michael O’Shaughnessy, was a busy man at the time: in addition to creating an airport, he had overseen the conception and construction of the Hetch Hetchy dam and multiple transportation and sewage tunnels throughout San Francisco. This image was posted on January 09, 2023.