In which nation were U.S. hostages held for 444 days between 1979 and 1981?

Iran

Answer: The Iran hostage crisis was a diplomatic standoff between Iran and the United States. On November 4, 1979, a group of Iranian students belonging to the Muslim Student Followers of the Imam’s Line, stormed the U.S. Embassy in Tehran taking more than 50 American hostages.

The students set their hostages free on January 21, 1981, 444 days after the crisis began and just hours after President Ronald Reagan delivered his inaugural address. The crisis is considered a pivotal episode in the history of Iran–United States relations.