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 thirty two feet to allow boats to pass underneath. The Portage Lake Lift Bridge is the widest and heaviest double decked vertical lift bridge in the world. The lower deck of the bridge was originally open to rail traffic, but this level is now closed to trains and is used in the winter for snowmobile traffic. Throughout the 1960s, 70s and 80s, the bridge was painted the same color as the Mackinac Bridge — cream and forest green — however, in the early 1990s, it was repainted in a cream and robins egg blue color scheme—exactly the same colors as the National Park Service's ship Ranger III—to some denoting Houghton as the "Gateway to Isle Royale".
