the NCR flag depicts a two-headed mutated bear, directly inspired by the California state's flag which depicts a one-headed bear (the Grizzly Bear). The national identity of the NCR was based off the the old world's California Republic, the 31st state of the United States of America to be admitted to the union. These states consisted of Shady Sands, Boneyard, Maxson, Dayglow, and the Hub. Three years later, the Republic was voted into existence as a federation of five founding states, organized around major settlements throughout California. This idea resonated with many inhabitants and wastelanders, and won popular support, leading to the creation of the New California Republic in 2186.

With the expansion of trade routes came cultural exchange, eventually culminating in a movement aimed at forming a national identity.

With the assistance of the Vault Dweller, who destroyed the Khans, Aradesh and his daughter Tandi led the community into prosperity. The NCR was formed when dwellers emerged from Vault 15 in the year 2097, before founding the town of Shady Sands. Ranger Jackson (Mojave Outpost commander)

Fallout new california wiki