A merchant domicile country is the country in which a company (merchant) has its business license, tax relationship, merchant account, and other business processes.
Click the following link to view a spreadsheet of supported domiciled countries:
Keeping the spreadsheet up to date is an ongoing project. Some gateways listed may not have full information presented.
If you use the Vantiv gateway, the provider of the gateway (Litle & Co.) supports multiple merchant domicile countries for international underwriting and processing, but you (the merchant) must also have a presence in the United States and/or United States Tax ID.