St. Clair River Tunnel

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St. Clair River between Port Huron, Michigan and Sarnia, Ontario, Port Huron, Michigan

Tunnel under St. Clair River on Canadian National Railroad in Port Huron



Photo From Michigan Historic Sites Online


Street View 


The St. Clair Tunnel was the first full-sized subaqueous tunnel built in North America. Joseph Hobson, the Chief Engineer, successfully combined three significant new technologies -- a tunnel shield driven by hydraulic rams; a cast iron tunnel lining; and the use of a compressed air environment. This tunnel eliminated a major bottleneck in the rail transportation system linking the American midwest with its eastern markets. -- Historic American Engineering Record (HAER MI-67)

A Michigan Historical Maker here reads: First International Tunnel

At this point the Grand Trunk Western Railroad tunnel, linking Port Huron with Canada, passes underneath Military Street. This international submarine railway tunnel -- first in the world -- was opened in 1891. The tunnel's total length is 11,725 feet, with 2,290 feet underwater. The tunnel operations were electrified in 1908 and completely diesalized in 1958. Tracks were lowered in 1949 to accommodate larger freight cars. During World War I, a plot to blast the tunnel was foiled.

The street view here is just above the entrance of the tunnel.

National Register information 

Posted to the National Register of Historic Places on October 15, 1970
Reference number
Architectural style
Other architectural type; Subaqueous tunnel
Areas of significance
Transportation; Engineering; Commerce
Level of significance
Evaluation criteria
C - Design/Construction; A - Event
Property type
Historic function
Current function
Period of significance
Significant years
1889; 1891
Number of properties
Contributing structures: 3
Non-contributing buildings: 2
Non-contributing structures: 2
Non-contributing objects: 1

Update Log 

  • October 2, 2012: New Street View added by Rattrak
  • August 27, 2010: New photos from Nathan Holth