land office — a government office for the transaction of business relating to public lands.
post office — an office or station of a government postal system at which mail is received and sorted, from which it is dispatched and distributed, and at which stamps are sold or other services rendered.
foreign office — the department of a government that handles foreign affairs.
patent office — (often initial capital letters) a governmental agency that administers and regulates patents and trademarks, in the U.S. forming a division of the Department of Commerce.