New United Motor Manufacturing, Inc. (NUMMI) was an American automobile manufacturing company in Fremont, California, jointly owned by General Motors and Toyota, that opened in 1984 and closed in April 2010. The plant is located in the East Industrial area of Fremont next to the Mud Slough between Interstate 880 and Interstate 680. The plant's peak production year was 2006, when it manufactured 428,633 vehicles.