No, they don't. One of the canons of statutory construction is a presumption against extraterritorial application of laws. Congress has to intend for a law to apply beyond US borders, and it's assumed they don't without evidence to the contrary.
In some cases they have done this, such as in the PROTECT Act of 2003 which contains a prohibition on child sex tourism. But there is no general assumption that US law applies everywhere.
In some cases they have done this, such as in the PROTECT Act of 2003 which contains a prohibition on child sex tourism. But there is no general assumption that US law applies everywhere.