The main entrances to Columbia's campus on Morningside Heights in Manhattan are at Broadway and 116th Street (where the subway station is) and at Amsterdam Avenue and 116th Street.
The best way to reach campus is using the subway. Take subway line number 1 or 9 local to 116th Street (Columbia University) station.
You may park on the street or use the local parking garages. The 512-520 Garage is located at the corner of 112th Street and Amsterdam; the Riverside Church Parking Garage is located on 120th Street between Claremont Avenue and Riverside Drive.
More transportation information is available from Maps and Directions page on the Columbia University web site.
The Schapiro Center for Engineering and Physical Science Research (Schapiro CEPSR) is at the northern end of Columbia University's Morningside Campus. The building is on 500 West 120th Street, between Broadway and Amsterdam, about half-way down the block on the south side. The Davis auditorium is on the 4th floor (campus level), room 412.
From the campus entrance, walk in along College Walk, head north up the steps, go around Low Library and to the back of Uris Hall (the Business School) to reach Davis Auditorium in Schapiro Hall.
Entering the building from 120th Street, you will come through a set of iron gates. Right in front of the gate there is an elevator that will take you up to the 4th floor, where the Davis Auditorium is located (you may also use the stairs).