Some information regarding California (note that this is a copy/paste from when I answered someone's question involving the history of California and Utah on Discord):
California was founded very early on (it is one of the very first nations in the Americas to follow the US's lead in revolting), and signed up to the US fairly late (late 1800s). It has historic ties to Mexico and some to England (After it was clear that England was going to lose NA, they started trying to influence nations/regions like California, in order to have an at least minor presence on the continent). The ethnic makeup is about %50-%50 white aka "Californian" to something that could be considered a subset of Mexican aka "Californio" (these terms are the best descriptions to use, and not "Yankee", or "English", or "Mexican/Latin-American" (at least for those who are native born)). The white portion of the population is %50-%50 (these aren't exact of course) English to Yankee, I feel like the Yankee doesn't need to be explained, as that group tends to spread itself all over NA, while the English is a result of England increasing its influence in the region/when British Canada fell, some fled to California. Early on in its history, it was a "Mexican" country, which slowly evolved over time. California has Spanish and English both as the Primary language (aka they area equal in the eyes of the government, and most officials are bilingual). California is one of the only States to be given a special exception when it comes to war, in that if the US goes to war with the UK/England, then California isn't required to join if it doesn't want to (this is the primary demand they had when they joined the US). Governmentally, California is a Parliamentary Democracy, a lot like OTL European countries (I even tend to think of it like OTL Europe, but in America), meaning that they have a plethora of parties, and everything that comes with the system. They are a light federation, where each department has its own power, however they have no illusion of being independent, like how the OTL US states do.