Legal Question in International Law in California

You must declare cash or bearer instruments valued at $10,000 or more whenever you enter or exit the US. You are free to take checks (not payable to "cash" or "bearer") in any amount without declaring them, and you can wire-transfer money in any amount, for example to an overseas account.

Emigrating from the US may have tax consequences. If you are a US citizen, the US IRS taxes you on your worldwide income, even if you leave and never return to the US. Some people renounce their US citizenship for tax reasons, this may have adverse consequences including possibly becoming unable to re-enter the US for more than a short time. The IRS may require you to pay taxes on your US assets at a stepped-up tax basis when you emigrate. Consult a tax lawyer. There are also, of course, numerous websites that discuss various aspects of expatriate life, including citizenship, visa, and financial issues.