Some States allow cities to spread across county lines, Texas does this. Some don’t allow this a City has to be entirely within its original County and contiguo

Some States allow cities to spread across county lines, Texas does this. Some don’t allow this a City has to be entirely within its original County and contiguous. That is how California does it, which has one city that merged with its county: San Francisco. In at least one case, there is a city that is composed of 5 entire counties: NYC.