Capitol building
Yes. It is located on the Capitol Mall.
The dc mall is about 1 mile in length(1.6km) and about 400 feet wide
There are several. The most famous one is the National Mall (no, not a shopping mall.) It is a strip of land that begins at the capitol building and ends at the Washington Monument, approximately.
It's not far at all. You can get to the Capitol (The end of the Mall) in probably mess than a quarter of a mile from Union Station.
Easy. Just walk towards the Capitol Building, you can see it when you leave the station. Once in front of the Capitol, turn right and walk along the Mall to the National Gallery, which will be on the right side of the Mall.
In Washington DC
The inauguration is held in Washington, D.C., on the National Mall.
SACREMENTO is the capitol
dc
The Capitol is the seat of the US Congress in Washington, DC.
because they do not have a mall