Abbreviations have changed over time. Make certain that you are interpreting the abbreviation in the context of the time and location in which it was created.
This immigrant trunk from the 1860-1870 era contains the abbreviation “Ills” for Illinois.That was pretty standard during the time. Other abbreviations were not.
“Ca” as a place of birth in an 1850 census record from New York State probably is a reference to Canada and not to California.