Interac e-Transfers are only available in Canada for individuals who have Interac-partnered bank accounts (most of them). So, no you cannot use Interac e-Transfer in the U.S. That being said, Interac does have a collaboration with Mastercard and Western Union to allow Canadians to send International Transfers.

International Transfer by Mastercard and Interac is a safe, fast and cost-effective way for Canadians to send money internationally from any bank account in Canada to bank accounts worldwide. Which countries can I send money to? You can send money to more than 75* countries worldwide from your Canadian bank account.