Iowa Code § 321G.8: Exempt snowmobiles.

Registration and nonresident user permits shall not be required for the following described snowmobiles:

1. Snowmobiles owned by the United States, this state, or another state, or by a governmental subdivision thereof, and used for enforcement, search and rescue, or official research and studies, but not for recreational or commercial purposes.

2. Snowmobiles used exclusively as farm implements.

3. Snowmobiles registered in an organized special event authorized pursuant to section 321G.16 when such snowmobiles are operated within the boundaries of the event.