You only do business in the United States (and/or Canada) and don't want to buy "International" leads.
You can use the IP Address information TrustedForm collects with each lead to determine the City, State, and Country from which the lead form was filled out.
The screenshot below shows how you should set up a filter to catch non-US leads.
NOTE: This filter assumes a TrustedForm certificate is NOT required to accept the lead.
NOTE: This feature is not compatible with TrustedForm for Facebook Lead Ads