The Alaska System is referred to by Liberty as "Zone 21". Not much is known about this system.
Only the Prison Station Mitchell and non-interactive Juneau Shipyards exist here. This system is visited in mission 11. Alaska is a top secret base for the Liberty Navy and LSF. It is speculated that experimental ships are being developed and/or nomad research. Juneau shipyard is probably where some, if not all, Nomad research takes place. Prison station Mitchell is probably used for hiding most wanted people or to store classified information.
During the storyline, Alaska was occupied by the Navy and the Nomads (most likely because all of the pilots are possessed). On the navy ships nomad weaponry is used possibly because either nomads occupy or the navy was already using it as a prototype.
"Did you hear in the news that there was an attack in Zone 21 after all? First the Navy denied it, but now they confirmed that The Order has taken out a cruiser near the entrance passage to the Zone. It's really scary how much damage an organization like The Order is able to inflict." - Bartender Bob Swaffar, Planet Manhattan.