When do I clear US customs and immigration if connecting at a US airport to my final destination elsewhere in the US?

Question

I'm a British citizen travelling from London Heathrow (LHR) to the Hartford, Connecticut airport, and have a two hour stopover in Newark, New Jersey (EWR) on my itinerary. At what stage would I clear immigration and customs on arriving in the USA?

Answer 1

Generally, you clear US customs and immigration at your first point of entry into the country. In your case, that is Newark.

There are a few airports outside the US that offer preclearance flights. (London Heathrow is not among them.) A preclearance flight is screened for US customs and immigration at departure, rather than arrival, so you arrive in the U.S. as if on a domestic flight. Preclearance is only available from (as of December, 2021):

16 Preclearance locations in 6 countries: Dublin and Shannon in Ireland; Aruba; Freeport and Nassau in The Bahamas; Bermuda; Abu Dhabi, United Arab Emirates; and Calgary, Toronto, Edmonton, Halifax, Montreal, Ottawa, Vancouver, Victoria, and Winnipeg in Canada.

See the edit history for earlier versions of this answer.

Answer 2

I encourage you to accept Nate Eldredge's answer, but I would like to add to it.

This is a very common question. People sometimes seem puzzled about the reason behind this practice; after all, why force travelers to undergo a potentially time-consuming examination while changing planes. They have enough stress, and the immigration and customs inspection only increases the probability of missing the connecting flight. There is a simple reason for it, however:

The second flight is a domestic flight. Some people on the plane, if not most, are domestic travelers who do not need inspection. In some cases, the destination of the domestic flight will be a domestic airport that does not have immigration or customs inspection facilities. Even if the final destination is an international airport, there is no provision for identifying which passengers from the domestic flight require immigration inspection and which do not.

The solution is to have arriving passengers disembark into an "international zone" for uninspected passengers and their goods, and to inspect them as they leave that zone. In the US, all passengers must leave the zone before boarding any flight, but in some countries it's possible to board an international departure without leaving the zone. This is sometimes called "sterile transit." Even where sterile transit is possible for an international departure, however, it is not possible for a domestic departure.