19 CFR § 4.3 - Vessels required to enter; place of entry.
(a) Formal entry required. Unless specifically excepted by law, within 48 hours after the arrival at any port or place in the United States, the following vessels are required to make formal entry:
(1) Any vessel from a foreign port or place;
(2) Any foreign vessel from a domestic port;
(3) Any vessel of the United States having foreign merchandise on board for which entry has not been made; or
(4) Any vessel which has visited a hovering vessel as defined in 19 U.S.C. 1401(k), or has delivered or received merchandise or passengers while outside the territorial sea.
(b) Completion of entry.
(1) When vessel entry is to be made at the customhouse, either the master, licensed deck officer, or purser may appear in person during regular working hours to complete preliminary or formal vessel entry; or necessary documents properly executed by the master or other authorized officer may be delivered at the customhouse by the vessel agent or other personal representative of the master.
(2) The appropriate CBP port director may permit the entry of vessels to be accomplished at locations other than the customhouse, and services may be requested outside of normal business hours. CBP may take local resources into consideration in allowing formal entry to be transacted on board vessels or at other mutually convenient approved sites and times within or outside of port limits. When services are requested to be provided outside the limits of a CBP port, the appropriate port director to whom an application must be submitted is the director of the port located nearest to the point where the proposed services would be provided. That port director must be satisfied that the place designated for formal entry will be sufficiently under CBP control at the time of entry, and that the expenses incurred by CBP will be reimbursed as authorized. It may be required that advance notice of vessel arrival be given as a condition for granting requests for optional entry locations. A master, owner, or agent of a vessel who desires that entry be made at an optional location will file with the appropriate port director an application on CBP Form 3171 and a single entry or continuous bond on CBP Form 301 containing the bond conditions set forth in § 113.64 of this chapter, in such amount as that port director deems appropriate but not less than $1,000. If the application is approved, the port director or a designated CBP officer will formally enter the vessel. Nothing in this paragraph relieves any person or vessel from any requirement as to how, when and where they are to report, be inspected or receive clearance from other Federal agencies upon arrival in the United States.