Embassies and consulates are part of the U.S. Department of State. Virtually every U.S. embassy and many U.S. consulates located in major cities worldwide have visa sections. However, not every consulate issues every type of visa. When you are ready to apply, you will have to locate the consulate nearest you that is authorized to issue the visa you want. Visa sections are subdivided into immigrant and nonimmigrant departments.
Some consulates handle only one type or the other.
If you find that a particular embassy or consulate with which you are familiar is missing from the pertinent list, it is because it is not authorized to perform immigration processing. When you apply for a green card at a U.S. embassy or consulate, you must usually do so in the country where you live. Embassies and consulates located in nations other than your home country will normally refuse to accept your case. Occasionally, a consulate in a country other than your present homeland may be persuaded to process your application, but those are exceptions and require advance approval. Furthermore, to get the right to apply in some other country, you must show a compelling reason why you are unable to apply at home.