Maximum allowable Currency for Visitor Visa

[miracle]

Hi,

My parents are coming on visitor visa to USA on British Airlines via London.
Does Any one know how much US dollar and British pound they can carry with them.
Is there any limitation?

Thanks for your help

[taco]

There is no limit to the currency you bring in to US but you must declare
if you are bringing USD 10,000 or more on the customs form given to you
on the plane and to the customs officer at entry.