Is card counting in a casino considered illegal?

No, you can't criminalize a thought process.

True, it is not illegal, but it's really treated like it is.

No, but you can't use any electronic devices or paper or anything to help and don't move your lips when you try to remember because then you'll most likely get kicked out.

Further although card counting, or counting cards, is just play the game extremely well. and this means more winnings for you and less profit for the casino. hence why when you are caught the casino asks you to leave. unfortunately you can't just walk in to the next casino, as they all use face recognition software to advise them of people already caught card counting. but good luck with your exploits!

yes i do agree from zanerr