Exhibit 21-A

OTTER TAIL CORPORATION

Subsidiaries of the Registrant
February 28, 2008

Company	State of Organization
Otter Tail Energy Services Company, Inc.		Minnesota
Overland Mechanical Services, Inc.		Minnesota
Green Hills Energy, LLC		Minnesota
Sheridan Ridge I, LLC		Minnesota
Sheridan Ridge II, LLC		Minnesota
Otter Tail Assurance Limited		Cayman Islands
Varistar Corporation		Minnesota
Northern Pipe Products, Inc.		North Dakota
Vinyltech Corporation		Arizona
T.O. Plastics, Inc.		Minnesota
St. George Steel Fabrication, Inc.*		Utah
DMI Industries, Inc.		North Dakota
DMI Canada, Inc.		Ontario, Canada
BTD Manufacturing, Inc.		Minnesota
ShoreMaster, Inc.		Minnesota
Galva Foam Marine Industries, Inc.		Missouri
Shoreline Industries, Inc.		Minnesota
Aviva Sports, Inc.		Minnesota
ShoreMaster Costa Rica, Limitada		Costa Rica
DMS Health Technologies, Inc.		North Dakota
DMS Imaging, Inc.		North Dakota
DMS Imaging Partners, LLC*		Delaware
DMS Imaging Partners II, LLC*		Delaware
DMS Leasing Corporation*		North Dakota
Midwest Construction Services, Inc.		Minnesota
Aerial Contractors, Inc.		North Dakota
Moorhead Electric, Inc.		Minnesota
Lynk3 Technologies, Inc		Minnesota
AC Equipment, Inc.		Minnesota
Ventus Energy Systems, Inc.		Minnesota
Foley Company		Missouri
Chassis Liner Corporation*		Minnesota
E. W. Wylie Corporation		North Dakota
Idaho Pacific Holdings, Inc.		Delaware
Idaho-Pacific Corporation		Idaho
Idaho-Pacific Colorado Corporation		Delaware
AWI Acquisition Company Limited		Prince Edward Island, Canada
AgraWest Investments Limited		Prince Edward Island, Canada

* Inactive