The International Fuel Tax Agreement (IFTA) is an agreement between 48 states and 10 Canadian Provinces that simplifies how interstate trucking companies pay fuel tax. The agreement makes it possible for companies to pay fuel tax for all jurisdictions with a single tax permit, as opposed to licenses for each individual state/province.
With the permit, trucking companies will track their mileage and fuel usage in each jurisdiction and submit this with a quarterly tax filing. Members of the IFTA will split this revenue.
IFTA is completed through your base state.