Access comprehensive data on electric power transmission lines in San Mateo County, California, tailored for GIS professionals involved in utility management and infrastructure planning. This dataset includes detailed information on four overhead AC transmission lines currently in service, with voltage classes from under 100 to 287 volts. Each record comes from authoritative sources like the California Independent System Operator and includes substations like Pittsburg to San Mateo and Serra to Homestead. The data, verified via imagery and other methods as recently as 2018, also contains specifics about line lengths and associated NAICS descriptions, offering valuable insights for spatial analysis and operational needs.