Between Johnstone & Beard, near 10th Street (portal site)
Port Huron, St. Clair County

Designation and Designation Date

• National Historic Landmark, listed April 19, 1993
• National Register, listed October 15, 1970
• Marker, erected July 27, 1962
• State Register, listed August 23, 1956

Architect, Builder, Designer(s)

• Joseph Hobson, designer

Significant Date(s), Notes

•  1891, tunnel opened

Significance Statement

The St. Clair River Tunnel is nationally significant as the first full-size subaqueous tunnel built in North America. Prior to its completion, a railroad had never been able to pass beneath a river. This accomplishment was not possible until engineers learned to combine three elements of tunnel construction: the shield method of excavating, the cast iron tunnel lining, and excavating in a compressed air environment. The St. Clair River Tunnel is important in the history of engineering because it was the world's first true test of the feasibility of constructing railroad (and later vehicular) tunnels through the soft, porous ground commonly found beneath rivers. This engineering advancement had an impact on our nation's broader historical development by breaking the rail transportation bottleneck which was caused by the difficulty of crossing the wide rivers upon which most of our major population centers were located.

For information about any of the programs described on this site, write the Michigan State Historic Preservation Office, Michigan Historical Center, P.O. Box 30740, 702 W. Kalamazoo St., Lansing, MI 48909-8240, or call us at (517) 373-1630.

(B&W etching: "The meeting of the great shields of the St. Clair River Railway Tunnel." Scientific American, LXIII, Sept. 13, 1899, p. 159.)