This is a draft (I'll probably edit it in place) of what I'm working on to post to CFB before /u/hythloday1 puts up her long study. Please let me know if things don't make sense or I need to explain things in better ways.
Review and History. The Port of Minneapolis is the northernmost port on the Mississippi River System. Located near the convergence of the Mississippi and the Minnesota Rivers, the Port of Minneapolis is about 17 nautical miles upriver (20 kilometers or 12 miles northwest by air) of its sister city, St. Paul. Seat of Hennepin County, Minnesota, the Port of Minneapolis and St. Paul form the Twin Cities conurbation.
SARNIA (Blue Water Bridge) The Blue Water Bridge port of entry, situated at the bridge connecting Point Edward, Ontario and Port Huron, Michigan, is the fourth largest land border port of entry for total traveller volumes entering Canada and the second largest for commercial vehicle volumes. The port of entry is open 24 hours a day, 7 days a week.