If neither candidate reaches the 270-vote threshold for victory in the Electoral College, the House of Representatives picks the president, according to a description of the process by the U.S. National Archives and Records Administration.
Every state delegation receives one vote in the process.
The Senate picks the vice president. Each senator has one vote.
If the House of Representatives does not elect a president by Inauguration Day, the vice president serves as acting president until the House of Representatives resolves the tie.