Here are a few from Northwestern Ontario. Lots of lakes, but not a lot of highways means lots of bridges. Some of which are actually impressive!
The Noden Causeway is a 5.5km long series of 3 bridges on Rainy Lake just east of Fort Frances, Ontario. The Causeway was completed in 1965 and linked the farthest reaches of Northwestern Ontario with Highway 11. The main span is 1.2km long.
Photo By Government of Ontario
The Sioux Narrows Bridge is located on Highway 71 and passes over a portion of Lake of the Woods. Opened in 1936, it was the longest single span wooden bridge in North America. Structural issues required the dismantling of the wooden bridge in 2002. In 2006 the new bridge was completed, with wood cladding on the steel structure to maintain the look of the original bridge.
Photo by Krazytea (wikipedia)
The Rainy River-Baudette Bridge is the westernmost international crossing in Ontario. The bridge represents the terminus of Yonge Street, some 1,984km from where it starts in downtown Toronto. It links the towns of Rainy River, Ontario and Baudette, Minnesota.
Looking from Canada towards the United States. In the background is the CN Rail bridge.
The Rainier Bridge is a rail bridge between Rainier, MN and Fort Frances, Ontario. It is one of the busiest rail ports of entry in the country. The bridge is located at Pither's Point where Rainy Lake feeds into the Rainy River. The bridge has a lift to accommodate marine traffic.