How old do you have to be to use a hotel?

I'm planning a big trip from my state of Maryland to San Diego, with a side trip to Six Flags Magic Mountain. I'm planning on going with three other friends. By the time we would go, only one of us will be 18. Will it be legal to be in a hotel room? We'll all be 16 or older though at the time of the trip.

18 is the age to get the room in the hotel room if they purchase then any one younger is fine

18 has to be the buyer and then anyone younger that attends is fine! Just make sure someone with you is 18! Have fun!!!