Exhibit 21-A
OTTER TAIL CORPORATION
Subsidiaries of the Registrant
February 20, 2020
| Company | State of Organization |
| Otter Tail Power Company | Minnesota |
| Otter Tail Assurance Limited | Cayman Islands |
| Varistar Corporation | Minnesota |
| Northern Pipe Products, Inc. | North Dakota |
| Vinyltech Corporation | Arizona |
| T.O. Plastics, Inc. | Minnesota |
| BTD Manufacturing, Inc. | Minnesota |