The Mill Cities Relay is is an invitational event that is open to all members of the following clubs:
Founding Clubs of the Mill Cities Relay (1984)
- Gate City Striders
- Greater LowellRoad Runners
- Merrimack Valley Striders
- Athletic Alliance Running Club
- Andovers Striders
- Gils Athletic Club
- Goon Squad
- Greater Derry Track Club
- Melrose Running Club
- Mystic Runners
- North Medford Club
- North Shore Striders
- Sandown Rogue Runners
- Shamrock Running Club
- Somerville Road Runners
- Squannacook River Runners
- TriFury
- Whirlaway Racing Team
- Wicked Running Club
- Winner’s Circle Running Club
