Livermore, city, Alameda County, western California; incorporated as a city 1900. It is a commercial and manufacturing hub in a region of vineyards and cattle ranches; products include electronic equipment, wine, processed food, and construction materials. Lawrence Livermore National Laboratory (1952), operated by the University of California, and other important centers for the research and development of laser and nuclear weapons and energy sources are in the area. Once part of Rancho Las Positas, which was granted to Robert Livermore in 1839, the community was laid out with the arrival of the railroad in 1869. Population 48,349 (1980); 56,741 (1990); 73,345 (2000).