PJM, or PJM Interconnection, is a regional transmission organization (RTO) in the United States. It coordinates the movement of wholesale electricity in parts of 13 states and the District of Columbia. PJM ensures that electricity supply meets demand while maintaining grid reliability and efficiency. Founded in 1927, PJM manages a competitive electricity market, allowing various energy producers to sell their power. It also oversees the planning and development of the transmission infrastructure needed to support the growing energy needs of the region.