Where We Operate


PJM ensures the reliability of the high-voltage electric power system serving 61 million people in all or parts of Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia and the District of Columbia. PJM coordinates and directs the operation of the region’s transmission grid, which includes 62,556 miles of transmission lines.

PJM Footprint & IRC

PJM shares borders and coordinates with other regional grid operators including Midcontinent Independent System Operator and New York Independent System Operator. Regional grid operators and independent system operators exist throughout the continent.

Both regional transmission organizations (such as PJM) and independent system operators (such as New York ISO) were formed to ensure the efficient and reliable delivery of power. RTOs are required to fulfill additional functions beyond the scope of ISOs. The FERC delineated twelve characteristics and functions that an entity must satisfy in order to become an RTO including that an RTO must be of sufficient regional scope.

The four minimum characteristics that an RTO must have are:

  • Independence
  • Scope and regional configuration
  • Operational authority
  • Responsibility for short-term reliability

The eight minimal functions that an RTO must perform are to:

  • Administer and design tariffs
  • Manage congestion
  • Solve the parallel path flow problem
  • Manage and provide ancillary services
  • Maintain Open Access Same-Time Information System and post the transmission capability
  • Perform market monitoring
  • Plan and manage transmission system expansion
  • Handle interregional coordination