America's First Subway Map

The first subway in the United States was built in Boston. The tunnel ran along Tremont Street,  a chaotic mess of streetcars, horse-drawn carriages and pedestrians. The tunnel was built to route the streetcars underground to ease congestion. Here is a plan of the original subway tunnels.

via Leventhal Map Center

The plan involved building a tunnel from North Station to the Boston Public Garden with two portals (where the streetcars emerge from underground) at the southwest end, one at the public garden and another along Tremont Street a few blocks south of the Boylston Street Station. 

This detail shows the latter of those portals, the Pleasant Street portal. Green lines indicate above ground sections while red lines are underground.

The streets in many parts of this plan are unrecognizable as they have fallen victim to various rounds of urban redevelopment. This portal was discontinued in 1962 and was buried underground. The disused tunnel still exists. Here is a detail of Boylston Station showing how the line to the south has to make its way underneath the line that curves to the west (west is up on this plan) making a sub-subway.

A plan showing the progress as of August 15, 1897 (a couple of weeks before its opening) is available from Boston in Transit.

The legend on this map is complicated and hard to translate but the text gives an idea of when various sections were completed.

These subway tunnels are still in use today, part of the MBTA Green Line. For a while this was part of my daily commute to work. The old tunnels are a bit claustrophobic and creepy but they still work!