Four States Commonwealth

The  was one of the thirteen commonwealths of the pre-war United States of America. Created in the early 21st century, it was comprised of the former states of Utah, Colorado, Arizona and New Mexico.

Known places

 * Bloomfield Space Center (Van Buren)
 * Boulder Dome (Van Buren)
 * Buena Vista (Fallout Tactics)
 * Flagstaff (Fallout: New Vegas Official Game Guide)
 * Denver (Fallout: New Vegas, Van Buren)
 * Grand Canyon (Fallout: New Vegas, Van Buren)
 * Maxson Bunker (Van Buren)
 * Mesa Verde (Van Buren)
 * The Nursery (Van Buren)
 * New Canaan (Fallout: New Vegas, Van Buren)
 * Ouroboros (Van Buren)
 * The Reservation (Van Buren)
 * Tibbets Prison (Van Buren)
 * Twin Mothers (Van Buren)
 * Two Sun (Fallout: New Vegas)
 * Vault 0 (Fallout Tactics)
 * Vault 29 (Van Buren)

Utah Wasteland
In 2062, many Mormon congregations came together to purchase places in Vault 70, a Vault-Tec Vault in Salt Lake City. Vault 70 opened in 2190 and its residents use their three G.E.C.K.s to found the city of New Jerusalem in the ruins of Salt Lake City. Most of the cities in Utah were destroyed in the Great War in 2077 and most of the state's current inhabitants are tribals (including the powerful Hecate of Ouroborus and the Blackfoot tribe). Burham Springs, with its horrible mutants is also located in the former Utah.

New Jerusalem's intolerant prophet and apostles repeatedly voted to have no commerce with outsiders from other, failed communities, refugees, or tribals. In 2233, a number of angry tribals, raiders, and disassociated attackers gang up on New Jerusalem and sack it, killing most of the Mormons in the process.

The new living prophet, Judah Black, led most of the remnants of the Mormon community north to Ogden, Utah. They establish the town of New Canaan.

After Caesar formed his legion, they took over the Utah Wasteland.

Arizona Wasteland
Before the war, Mr. House, RobCo and Vault-Tec created a PDQ-88b securitron Vault under Fort Drawbridge. After the war, it was the birthplace of the Caesar's Legion. The Caesar's Legion enslaved the entire state, before heading north to New Vegas and the Mojave Wasteland. The Legion returns to Arizona if defeated at the second battle of Hoover Dam. The legions main base, Fortification Hill and Fort Drawbridge are located here.

New Mexico Wasteland
The New Mexico Wasteland was taken over by Caesar's Legion. The Reservation is located here.

Southern Colorado
The legion took over the southern area, and get their dogs from Dog City.

Appearances
Parts of the former Four States Commonwealth appear in Fallout Tactics and Fallout: New Vegas.. Most of the places in Van Buren and Fallout d20 were located there as well.