A K-1 visa is a visa issued to the fiancé or fiancée of a United States citizen to enter the United States. A K-1 visa requires a foreigner to marry his or her U.S. citizen petitioner within 90 days of entry, or depart the United States. Once the couple marries, the foreign citizen can adjust status to become a lawful permanent resident of the United States (Green Card holder). Although a K-1 visa is legally classified as a non-immigrant visa, it usually leads to important immigration benefits and is therefore often processed by the Immigrant Visa section of United States embassies and consulates worldwide.
In 2014, the Department of State issued a total of 35,925 "K1" visas to fiancées of U.S. citizens. Including derivative categories—mostly for children of fiancées—a total of 41,488 visas in the K category were issued.
The K visa category was established in 1970, during U.S. involvement in the Vietnam War. The U.S. military required that Vietnamese citizens who wished to marry a U.S. soldier obtain both an exit visa from the Vietnamese authorities and an immigrant visa from the U.S. Embassy. Obtaining these documents was a time-consuming process and involved acquiring medical and police clearances for the Vietnamese citizen, and notarized Embassy certificates from the American. Many couples could not complete the process before the soldier had to depart for the U.S. When this happened, the Vietnamese citizen would be ineligible to receive a visitor visa to America as an intending immigrant. Immigrant visa numbers were also unavailable. In 1970, about 100 American-Vietnamese couples found themselves in this situation, resulting in considerable Congressional correspondence with the Embassy. On April 7, 1970, congress passed Public Law 91-225, which amended the Immigration and Nationality Act of 1952 and created the K visa category.
Today, U.S. law allows several ways for an American citizen to petition for a foreign loved one to immigrate to the United States. Immigrant visas are available for an American to marry his or her spouse in a foreign country and then petition the spouse to immigrate to the United States. Spouses of U.S. citizens receive immediate preference to immigrate to the United States. However, in some cases a foreign citizen and an American citizen cannot legally marry in a foreign country, even though the marriage would have no legal impediments in the United States. For example, some countries require a parent's permission to marry even for adults, or forbid marrying outside of one's religion or ethnic group. Additionally, some couples prefer to have their wedding in the United States. It is in these circumstances such that a K-1 visa is especially useful.