Portage Lake Lift Bridge

The Portage Lake Lift Bridge (officially the Houghton–Hancock Bridge) connects the cities of Hancock and Houghton, in the US state of Michigan, across Portage Lake, a portion of the waterway which cuts across the Keweenaw Peninsula with a canal linking the final several miles to Lake Superior to the northwest. US Highway 41 (US 41) and M-26 are both routed across the bridge.

The original bridge on this site was a wooden swing-bridge built in 1875. This bridge was built by James P. Edward of Fox and Howard Inc. of Chicago. Three local men raised $47,000 in stocks for the toll bridge. Construction began in the spring of 1875 and was finished in the spring of 1876. This was replaced by a steel swing-bridge built by the King Bridge Company in 1901. This bridge was damaged when a ship collided with it in 1905. The center swinging section of the bridge was replaced and a similar incident almost occurred again in 1920, but the ship was able to stop by dropping its anchor, which snagged on the bottom of the lake. In 1959, this bridge was replaced, at a cost of about 11-13 million US dollars (sources vary), by the current bridge which was built by the American Bridge Company.

As its name states, the bridge is a lift bridge with the middle section capable of being lifted from its low point of four feet clearance over the water to a clearance of 100 feet (30 m) to allow boats to pass underneath. The Bridge is the world's heaviest and widest double-decked vertical lift bridge. More than 35,000 tons of concrete and 7,000 tons of steel went into the bridge, which replaced the narrow 54-year old swing bridge, declared a menace to navigation on the busy Keweenaw Waterway. Its center span "lifts" to provide 100 feet (30 m) of clearance for ships. The bridge is a crucial lifeline, since it is the only land based link between the north (so-called Copper Island) and south sections of the Keweenaw peninsula.

The lower deck of the bridge was originally open to rail traffic, but this level is now a road and it is raised up to road level in the summer for cars. This is done so that smaller boats may pass below without needing to disrupt car traffic. It is lowered in the winter, when ice prevents boats, so that snowmobile traffic can enter under the roadway.

Hancock and Houghton hold an annual celebration called Bridgefest to commemorate the opening of the bridge which united their two communities.