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1. Capital was previously founded
Sacramento — 1848, Mexicali — 1903
3. Is a state
State of California is an American state; Free and Sovereign State of Baja California is a Mexican state
4. It has access to the Gulf of California
U. S. California hasn't any access to this gulf
5. Is most populated subdivision in their own countries
Baja California is only in 14th place among the Mexican states
6. Has bigger city proper capital population
Sacramento even has more urban population than Mexicali
8. ... Has own Death Valley
Only California has Death Valley
9. Has their own name on their flags
California: "California Republic", Baja California: "Baja California"
10. ... Was previously inhabited by Europeans
Baja California — 1539, California — 1542
11. ... Was ruled by Dominicans
Franciscans missionaries ruled in both Californias, Dominicans ruled only in Baja California
12. Is bigger than Baja California Sur
Baja California — 71,450 km², Baja California Sur — 73,909 km², California — 423,970 km²
13. ...Closer to New Mexico
Your vision is right — California is closer, at least a couple dozen miles