The travel.state.gov site has information about obtaining a visa for those traveling to the United States. The site also has links to websites for U.S. embassies and consulates worldwide. The embassy and consulate websites have very helpful information about procedures, timelines, communities served, required documentation, and fees.
Please note: International registrants should be particularly aware and careful about visa requirements and should plan travel well in advance.
The Association for Computing Machinery (ACM) does not issue formal invitation letters for visas. ACM is able to provide visa support letters to attendees as well as authors with accepted papers, posters, or members of the conference committee. All visa inquiries must be handled by ACM HQ. Please send your request for a letter in support of a visa application to firstname.lastname@example.org and include the following information:
Those requesting a letter should allow 7-10 business days to receive it. All requests are handled in the order they are received.