It's about 46 square miles, smaller than Fargo, North Dakota. How come it didn't annex areas south of it, including the area that has the San Francisco Airport? I recognize that below it is a different county, but why not annex the northern parts and combine it with the consolidated San Francisco city-county?
There was a proposal to annex San Mateo and form some sort of consolidated government. I think that San Mateo (or the urban parts adjacent to San Francisco) would have been made a borough. I think this was around 1920 or so, but it was defeated. Remember that New York City wasn't converted to its modern form until the early 20th Century, when Brooklyn was annexed, the southern tip of the mainland chopped from Westchester to become the Bronx, and eastern Queens chopped off to become Nassau County, while Queens was annexed.
IIRC, there was some other proposal that would have partially annexed Daly City, maybe so that it could get water from Hetch Hetchy.
