U.S. flag

An official website of the United States government

Dot gov

Official websites use .gov

A .gov website belongs to an official government organization in the United States.


Secure .gov websites use HTTPS

A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites..

Single Building

A building that is separated from other buildings by intervening clear space or solid, vertical, load-bearing division walls.

Last updated March 5, 2020