Which waterfall lies on the border between the United States and Canada?

Niagara Falls lies on the international border between the United States and Canada, where the Niagara River drops from Lake Erie toward Lake Ontario. The falls span Ontario on the Canadian side and New York on the U.S. side.

Niagara Falls is actually a group of three falls: Horseshoe Falls, American Falls, and Bridal Veil Falls. Horseshoe Falls is the largest and straddles the border, while American Falls and Bridal Veil Falls lie entirely within the United States. This three-part structure is why the name refers to a group rather than one single cascade.

The falls formed after glaciers reshaped the Great Lakes region and exposed a resistant rock ledge in the Niagara River. Erosion continues to move the brink upstream, although dams, diversion tunnels, and engineering controls have reduced the natural rate.

Niagara is both a landmark and a major power source. Hydroelectric facilities on both sides divert part of the river’s flow, while the 1950 Niagara Treaty regulates diversions to preserve the falls’ appearance. A frequent mistake is calling all three sections Canadian: only Horseshoe Falls crosses the border.