Approximately 90% of the Niagara River, after diversions for hydropower generation, flows over Horseshoe Falls.

It is located between Terrapin Point on Goat Island in the US state of New York, and Table Rock in the Canadian province of Ontario.

[3][4] When the boundary line between the United States and Canada was determined in 1819, based on the Treaty of Ghent, the northeastern end of the Horseshoe Falls was in New York, United States, flowing around the Terrapin Rocks, which were once connected to Goat Island by a series of bridges.

In 1955, the area between the rocks and Goat Island was filled in, creating Terrapin Point.

[5] In the early 1980s the United States Army Corps of Engineers filled in more land and built diversion dams and retaining walls to force the water away from Terrapin Point.