Tips for New Importers of Goods Into the USA
To avoid potential problems in the clearance of your merchandise, “US Customs and Border Protection (CBP) strongly recommends that you familiarize yourself with CBP policies and procedures prior to actually exporting your goods” to the 50 states:
https://www.cbp.gov/trade/basic-import-export/importer-exporter-tips
A guide for commercial importers:
https://www.cbp.gov/sites/default/files/documents/Importing%20into%20the%20U.S.pdf
Key business links:
https://uk.usembassy.gov/business/key-business-links/
The US Embassy in London may be able to advise on specific questions for British firms.
Contact:
CBP Representative
American Embassy
33 Nine Elms Lane
Nine Elms
London SW11 7US
United Kingdom
Tel: +44-(0)207-894-0070
The US Embassy in Ottawa may be able to advise on specific questions for Canadian firms. Contact:
CBP Attaché
Embassy of the United States
P.O. Box 866 station B
Ottawa, Ontario K1P 5T1
Canada
Tel: +1-613-688-5496