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1. . . . is larger? (area)
2. . . . has a greater population?
3. . . . was admitted to the union first?
Texas: 1845
California: 1850
4. . . . is the birthplace of more presidents?
Eisenhower and LBJ were born in Texas. Nixon was born in California. (Reagan was born in Illinois.)
5. . . . has the larger largest city?
6. . . . has more cities with population greater than 1 million?
Texas: 6
California: 5
7. . . . has more water area?
8. . . . covers a greater range of temperatures? (difference between record high and record low)
9. . . . was settled by Europeans first?
Ysleta: 1680
Santa Cruz: 1769
10. . . . had a "Big Four" (MLB, NFL, NBA, NHL) professional sports team first?
California beats Texas in all 4:
Los Angeles Dodgers & San Francisco Giants: 1958
Houston Astros: 1962
Los Angeles Rams: 1946
Dallas Cowboys: 1960 (Or the short-lived Dallas Texans, who didn't even finish their one season in Texas: 1952)
Los Angeles Lakers: 1960
Houston Rockets: 1971
California Seals: 1967
Dallas Stars: 1993
11. . . . has more UNESCO World Heritage Sites?
Redwood and Yosemite for California, San Antonio Missions for Texas
12. . . . has multiple buildings over 1,000 feet tall?
13. . . . has a city with more than 30 skyscrapers?
Houston has 38.
14. . . . has a higher Hispanic/Latino population (by percentage)?
15. . . . has a higher Native American population (by percentage)?
16. . . . is "taller"? (greater distance between northernmost and southernmost points)
17. . . . borders more U.S. states?
18. . . . has the busiest airport?
19. . . . has more interstate highway mileage?
Texas, unsurprisingly, is #1 in the U.S. in terms of interstate highway mileage.
20. . . . has the larger city named Pittsburg? (city proper population)
Pittsburg, CA: 70,679
Pittsburg, TX: 4,497