Four regions are incorporated under IRP’s umbrella:

Region I
Connecticut, Delaware, the District of Columbia, Maine, Maryland, Massachusetts, New Brunswick, Newfoundland, New Hampshire, New Jersey, New York, Nova Scotia, Ontario, Pennsylvania, Prince Edward Island, Quebec, Rhode Island and Vermont

Region II
Alabama, Arkansas, Florida, Georgia, Kentucky, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, Tennessee, Texas, Virginia, and West Virginia

Region III
Illinois, Indiana, Iowa, Kansas, Manitoba, Michigan, Minnesota, Missouri, Nebraska, North Dakota, Ohio, South Dakota and Wisconsin

Region IV
Alberta, Arizona, British Columbia, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Saskatchewan, Utah, Washington, and Wyoming