The 2008 CIA World Factbook

by United States. Central Intelligence Agency

Uganda
slightly smaller than Oregon

Ukraine
slightly smaller than Texas

United Arab Emirates
slightly smaller than Maine

United Kingdom
slightly smaller than Oregon

United States
about half the size of Russia; about three-tenths the
size of Africa; about half the size of South America (or slightly
larger than Brazil); slightly larger than China; more than twice the
size of the European Union

United States Pacific Island Wildlife Refuges
Baker Island: about
two and a half times the size of The Mall in Washington, DC
Howland Island: about three times the size of The Mall in
Washington, DC
Jarvis Island: about eight times the size of The Mall in Washington,
DC
Johnston Atoll: about four and a half times the size of The Mall in
Washington, DC
Kingman Reef: a little more than one and a half times the size of
The Mall in Washington, DC
Midway Islands: about nine times the size of The Mall in Washington,
DC
Palmyra Atoll: about 20 times the size of The Mall in Washington, DC

Uruguay
slightly smaller than the state of Washington

Uzbekistan
slightly larger than California

Vanuatu
slightly larger than Connecticut

Venezuela
slightly more than twice the size of California