Although the United States has many consulates abroad, not all of them handle every type of visa application. In some countries, certain applications are centralized at one location – and that location may not be the main embassy. Because these locations can change from time to time, it is very important to check before applying to make sure that everything goes to the correct place.
As an example, the Department of State recently announced that all K-1 (fiancée) visa applications for Canada will now be handled by the U.S. Consulate in Montreal. Until now, Canadian K-1 applicants on the west coast could have their visa interviews in Vancouver, but everything will be centralized in Montreal on April 1. While this change will help USCIS administer the visas, it will cause a new burden for some applicants. For some who are not aware of the change, it will come as a real shock when they learn that they now have to travel thousands of miles for their visa interview.
Always check filing and interview locations before filing a visa application. You can’t change the rules, but at least you will know what to expect.