Tesla Factory. This article is about the Tesla factory in Fremont, CA, USA. For the factory in Nevada, see Gigafactory 1. For the factory in Europe, see Gigafactory 2. The Tesla Factory is an automobile manufacturing plant in south Fremont, California, and the principal production facility of Tesla, Inc.. The facility was formerly known as New United Motor Manufacturing, Inc. (NUMMI), a joint venture between General Motors and Toyota.