Minnesota's last remaining covered bridge, the Zumbrota Covered Bridge, is located in Zumbrota, Minnesota in Goodhue County. In 1869, the Stafford Western Emigration Company contracted a member of their organization to construct the bridge. On its original location the bridge channeled the stage coach traffic between Dubuque, Iowa and St. Paul through the small village of Zumbrota.

The bridge was constructed at a cost of $5,800 by a local carpenter using the town lattice truss design. As initially constructed, the bridge was built with white-pine timbers used for the structural supports and the floor, and the planks were pinned together with turned white-oak dowels. The dowels were soaked in linseed oil and coated with a red iron oxide in order to preserve them from the elements.

Shortly after the bridge was constructed, the Stafford Western Emigration Company enclosed it with weatherproof sides and portals and a low gabled roof with cedar shingles. A vertical board-and-batten exterior trim was added to the sides and portals. The enclosure was completed by 1871 and served to lengthen the life of the structural supports beyond their normal projected twenty years of serviceability.

Excerpt from: http://www.zumbrota.com/bridge.htm