Remove Country and non-US states from Checkout Billing Info

Does anyone know how to completely remove the Country option and all non-US states from the State dropdown in the Billing form in checkout? Can I do this from the Admin backend or is this code that needs to be re-written. My Zen Cart "webmaster" has left me high and dry and I can't figure it out. Meanwhile, people are ordering from outside the US and I do not want to accept orders from outside the US. Help!

Any info is appreciated!

You could just build a Zone for the United States and what parts of the United States you do take orders for ...

All Zones would include a the States, DC, US Territories and Islands as well as the Armed Forces ...

If you add just the States and DC individually then only the States and DC can checkout ...

Add the Zone to your Payment Module(s) and Shipping Module(s) ... or If you accept Payment from ANYWHERE do not add the Zone to your Payment Modules and just add to your Shipping Module(s) ...