In addition to the normal visa regulations and required documentation, US citizens must have an MFA-approved guide to accompany them for the entire trip and must have an exact itinerary.
This generally precludes crossing into Iran at any border, as your guide would have to meet you at the border (Airport).
US citizens can apply for a visa at the Iranian Interest Section of the Pakistani Embassy in Washington.
To get the visa, US citizens must work in advance with an approved Iranian travel agency (i.e. IncredibleIran.com) to set up a guided itinerary; only then, that travel agency may apply for a visa authorization number from the Iranian Ministry of Foreign Affairs. Once approved, the authorization number is transmitted to the interest section.
We process dozens of visas for our American guests on a monthly basis and we have made everything easy, all we need from you is the information and we’ll take care of the rest, such as your detailed itinerary and your authorization number.
Should you require further information, please don’t hesitate to contact our visa specialist at email@example.com