Question: How long ago was the Wisconsin glaciation?
About the article "Niagara Falls", section "Geology".

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The Bull Lake glaciation is the name of a glacial period in North America that is part of the Quaternary Ice Age.
The Bull Lake glaciation began about 200,000 years ago and ended about 130,000 years ago, and was concurrent with the Illinoian Stage of the Quaternary Ice Age.
There is disagreement over these time frames, however, and further research is necessary.
This glacial period was identified by geologist Eliot Blackwelder.
The glacial period draws its name from Bull Lake in Wyoming in the United States, where well-preserved moraines from this glacial period were first described.
Although Blackwelder originally believed the Bull Lake glaciation occurred during the early Wisconsin Glaciation (the last major advance of glaciers in the North America), new data generated and described by geologist Gerald M. Richmond in the 1940s and 1960s more accurately dated the glacial period to the Illinoian Stage.
The Bull Lake glaciation was a local glaciation.
It did not cover the entire North American continent but rather just the eastern slopes of the southern Rocky Mountains.
Generally speaking, it extended from northwestern Montana south to the San Juan Mountains in Colorado.
The Bull Lake glaciation has three periods—Early, Middle and Late—punctuated by periods of relative warmth (during which glaciers retreated).
The Bull Lake glaciation is generally considered to be much less extensive than the preceding glaciations.
However, the reach of the glaciers varied from place to place, extending further in some areas than others.
Bull Lake moraines remain relatively undisturbed, indicating that glacial periods which came later were only about 90 percent as extensive as the Bull Lake glaciation.
The Bull Lake Glaciation was followed by a warm interglacial period that lasted about 60,000 years.
The Pinedale Glaciation, another local glacial period, occurred after this warm period. 
The Wisconsin Glacial Episode, also called the Wisconsinan glaciation, was the most recent major advance of the North American ice sheet complex.
This advance included the Cordilleran ice sheet, which nucleated in the northern North American Cordillera, the Innuitian ice sheet, which extended across the Canadian Arctic Archipelago, the Greenland ice sheet, and the massive Laurentide ice sheet that covered the high latitudes of central and eastern North America.
This advance was synchronous with global glaciation during the last glacial period, including the North American alpine glacier advance, known as the Pinedale glaciation.
The Wisconsin glaciation extended from approximately 85,000 to 11,000 years ago, between the Sangamon interglacial (known globally as the Eemian stage) and the current interglacial, the Holocene.
The maximum ice extent occurred approximately 25,000–21,000 years ago during the last glacial maximum, also known as the "Late Wisconsin" in North America.
This glaciation radically altered the geography of North America north of the Ohio River.
At the height of the Wisconsin Episode glaciation, the ice sheet covered most of Canada, the Upper Midwest, and New England, as well as parts of Idaho, Montana and Washington.
On Kelleys Island in Lake Erie or in New York's Central Park the grooves left by these glaciers can be easily observed.
In southwestern Saskatchewan and southeastern Alberta, a suture zone between the Laurentide and Cordilleran ice sheets formed the Cypress Hills, the northernmost point in North America that remained south of the continental ice sheets.
During much of the glaciation, sea level was low enough to permit land animals, including humans to occupy Beringia (the Bering Land Bridge) and move between North America and Siberia.
As the glaciers retreated, glacial lakes were breached in great floods of water such as the Kankakee Torrent which reshaped the landscape south of modern Chicago as far as the Ohio and Mississippi rivers. 
Life affects climate through its role in the carbon and water cycles and such mechanisms as albedo, evapotranspiration, cloud formation, and weathering.
Examples of how life may have affected past climate include: glaciation 2.3 billion years ago triggered by the evolution of oxygenic photosynthesis, glaciation 300 million years ago ushered in by long-term burial of decomposition-resistant detritus of vascular land plants (forming coal), termination of the Paleocene-Eocene Thermal Maximum 55 million years ago by flourishing marine phytoplankton, reversal of global warming 49 million years ago by 800,000 years of arctic azolla blooms, and global cooling over the past 40 million years driven by the expansion of grass-grazer ecosystems. 
The Marinoan glaciation was a period of worldwide glaciation that lasted from approximately 650 to 635 Ma (million years ago) during the Cryogenian period.
The glaciation may have covered the entire planet, in an event called the Snowball Earth.
The end of the glaciation may have been sped by the release of methane from equatorial permafrost. 
Named local glaciations.
Pinedale or Fraser glaciation, Rocky Mountains, USA.
The Pinedale (central Rocky Mountains) or Fraser (Cordilleran ice sheet) glaciation was the last of the major glaciations to appear in the Rocky Mountains in the United States.
The Pinedale lasted from approximately 30,000 to 10,000 years ago and was at its greatest extent between 23,500 and 21,000 years ago.
This glaciation was somewhat distinct from the main Wisconsin glaciation as it was only loosely related to the giant ice sheets and was instead composed of mountain glaciers, merging into the Cordilleran Ice Sheet.
The Cordilleran ice sheet produced features such as glacial Lake Missoula, which would break free from its ice dam causing the massive Missoula floods.
Geologists estimate that the cycle of flooding and reformation of the lake lasted an average of 55 years and that the floods occurred approximately 40 times over the 2,000 year period between 15,000 and 13,000 years ago.
Glacial lake outburst floods such as these are not uncommon today in Iceland and other places.