On the 8th floor of the Northwest Corner Building of Columbia University is a lactation room containing comfortable chairs for moms, there's a sink, and refridgerator where they can store pumped breast milk for later feeding.
The room accomodates nursing mothers around the clock so no need to worry about being too late to use it.
Contact the Office of Work/Life for access code, hours of operation are below:
24 hour access;7days/week- access available at campus level on the 4th floor