what two countries share a border with the great lakes?
Canada United States of America
entailment
 In Mexico , topographical officer George W. Hughes reported to Secretary of State John M. Clayton that a railroad across the isthmus was a “ feasible and practical ” idea . Clayton then instructed Robert P. Letcher , the minister to Mexico , to negotiate a treaty to protect Hargous ' rights . The United States ' proposal gave Mexicans a 20 % discount on shipping , guaranteed Mexican rights in the zone , allowed the United States to send in military if necessary , and gave the United States most @-@ favored @-@ nation status for Mexican cargo fees . This treaty , however , was never finalized . 

entailment
 While the border on land was firmly set in the early 20th century , the two states were still in disagreement on the path of the border to the east , in Lake Erie . In 1973 , the two states finally obtained a hearing before the United States Supreme Court on their competing claims to the Lake Erie waters . In Michigan v. Ohio , the court upheld a special master 's report and ruled that the boundary between the two states in Lake Erie was angled to the northeast , as described in Ohio 's state constitution , and not a straight east – west line . One consequence of the court decision was that tiny Turtle Island just outside Maumee Bay and originally treated as being wholly in Michigan , was split between the two states . 

neutral
 The main two international organizations which have been involved in the naming dispute are the International Hydrographic Organization and the United Nations . 

entailment
 The immense volume of water in the five Great Lakes holds heat that allows the lakes to remain relatively warm for much later into the year and postpones the Arctic spread in the region . During the autumn months , two major weather tracks converge over the area . Cold , dry air moves south / southeast from the province of Alberta and northern Canada ; warm , moist air moves north / northeast from the Gulf of Mexico , along the lee of the central Rocky Mountains . The collision of these masses forms large storm systems in the middle of the North American continent , including the Great Lakes . When the cold air from these storms moves over the lakes , it is warmed by the waters below and picks up a spin . As the cyclonic system continues over the lakes , its power is intensified by the jet stream above and the warm waters below . 

contradiction
 This decision was the last border adjustment , putting an end to years of debate over the official boundary line . In modern times , although a general rivalry between Michiganders and Ohioans persists , overt conflict between the states is restricted primarily to the Michigan – Ohio State rivalry in American football and to a lesser degree between the rivalry between the Detroit Tigers and Cleveland Indians in American League baseball ; the Toledo War is cited as the origins of the animosity represented in today 's rivalry . 
