Customs Waters Law and Legal Definition
“The term "customs waters" means, in the case of a foreign vessel subject to a treaty or other arrangement between a foreign government and the United States enabling or permitting the authorities of the United States to board, examine, search, seize, or otherwise to enforce upon such vessel upon the high seas the laws of the United States, the waters within such distance of the coast of the United States as the said authorities are or may be so enabled or permitted by such treaty or arrangement and, in the case of every other vessel, the waters within four leagues of the coast of the United States.” (19 USCS § 1401)