New California, also called the Core Region, is what remains of the west coast of the North American continent, including southern Oregon, western Nevada, and California. Major settlements in the Core Region emerged either from preexisting settlements from before the Great War or from the vaults that dot the region; prominent settlements include the Los Angeles Boneyard, New Reno, San Fransisco, the Hub, Vault City and Shady Sands.
The Children of the Cathedral, the cult branch of Unity dictated by the Master, held influence in the Core Region until they were defeated by The Vault Dweller from Vault 13 in 2162. The Enclave held a hidden though powerful presence in the Core Region until their main base of operations, an offshore oil rig was destroyed in 2242 by the Chosen One, a descendant of the Vault Dweller. After Unity was gone and while the Enclave were crippled and emigrating east, the New California Republic (est. 2186) grew out of Shady Sands and came to dominate the region, soon following a policy of expansion.