NPA - 671 (Guam)
The 671 area code is part of geographic numbering plan area that includes Guam.
There are a few special area codes with the last two digits 422 match, these are known as easily recognizable codes (ERCs). The 8xx set of numbers are reserved for toll-free services and communication.
Guam is an organized territory of the United States in Micronesia in the western Pacific Ocean. Guam has been a member of the Pacific Community since 1983 and the inhabitants of Guam are called Guamanians.
The US Military has a significant number of bases located on the island that in total cover 29% of the island's total land area:
U.S. Naval Base Guam, U.S. Navy
U.S. Coast Guard Sector Guam
Andersen Air Force Base, U.S. Air Force
Ordnance Annex, U.S. Navy
Naval Computer and Telecommunications Station, U.S. Navy
Joint Force Headquarters-Guam, Guam National Guard
The U.S. military has proposed building a new Nimitz-class aircraft carrier berth on Guam, this would also include moving thousands of service personnel along with their families to the islands.