Regardless of your final destination, you and your luggage will go through Customs at the first US based airport that you land in, even if you are making a connection and continuing onto another city. Make sure you have enough time to pass Customs and, if necessary, go to a different terminal to catch your connecting flight.

TIP:  If you are checking your luggage you will have to go back to the airlines counter and recheck your bags. Then you will pass through security to get to your gate.  Make sure you have enough time!

TIP:  Rechecking luggage is one more reason to seriously consider taking only carry on luggage.  See the section Should I check my luggage or carry it on with me for more information on how and why to do this.