Can I set up the store to take orders from US orders only?

In another word, can we block all the orders that don't have a US credit card address?

Thanks in adv

I don't know if there is an algorithm that can identify card numbers that are issued in the USA. (Card providers / banks and their geo-location can be identified by their card numbers). If you can find this out, there may be a way to write a bit of code that rejects card numbers that are not issued in the USA.

Quickfix is just to delete all countries, except USA. This will not allow customers outside of USA to register.

Hi there
I do exactly that for my site, BudgetHandles.com.au where I only accept orders from Australia. What you need is to define a zone (admin > Locations/Taxes) called USA and in list all the USA states as zones and then in your shipping module(s) set the zone to USA

Some paid merchant accounts require a billing address verification and allow you do define where orders are allowed from. Another suggestion is look in to not allowing country IPs other than US IP addresses, though that really wouldn't deter a scammer, just accidental orders.