Hachioji is a large city (population 551,901) located about 40 kilometres to the west of the central 23 wards of Tokyo.
The population density of Hachioji is much less than central Tokyo. Consequently, there are lots of natural areas within the cities boundaries including the easily accessible Mount Takao in the southwest corner of the city.
Hachioji station is served by the JR Chuo Line and the Keio Main Line which both provide direct access to Shinjuku. Stations further to the west are much smaller than Hachioji so if you need to break up a trip out to the hiking spots further to the west to pick up supplies, Hachioji is a good place to stop.