US Pre-Clearance Declaration Requirement

See 31 U.S.C. §§ 5316, 5317, 5324, and 5332.  Family members traveling together that file a family declaration must file this report (FinCEN 105) when the total combined amount of currency or other monetary instruments that is carried by the family members is over U.S. $10,000 (or foreign equivalent).  

If someone else transports, mails or ships currency and/or monetary instruments in an aggregate amount exceeding U.S. $10,000 (or its foreign equivalent) into or out of the United States on your behalf, then you are also required to report the total amount to CBP.
 
Failure to comply with these requirements may result in civil and criminal penalties and may lead to forfeiture of your monetary instrument(s).  For further information regarding these legal requirements, please consult the Currency and Foreign Transactions Reporting Act (P.L. 97-258, 31 U.S.C. 5311, et seq.) and its implementing regulations (31 CFR Part 1010).