What Region is California in?

When asking what region California is in would depend on what you are meaning by region. If you are talking about the census department California is in Region 4 the west region Division 9. Then you have the Standard Federal Regions which California falls in Region lX. Of course you have the time zones and California would be in Pacific time. You can find more information here: en.wikipedia.org/wiki/List_of_regions_of_the_United_States