Dunder Mifflin Paper Company is a fictional company in the television series The Office. It is the main setting for the show.
According to NBC.com:
"Dunder-Mifflin Inc. (stock symbol DMI) is a mid-cap regional paper- and office-supply distributor with an emphasis on servicing small-business clients. With a corporate office in New York City, Dunder-Mifflin has branches in Buffalo, Stamford, Albany, Utica, Scranton, Akron, Camden, Nashua and Yonkers."
There was once another branch located in Pittsfield, but due to workers trying to unionize, it was shut down.