Humans first arrived in the Don River area approximately 12,500 years BP, most likely as nomadic hunters.
While there is little archaeological evidence in the Don valley itself, regional finds in the Great Lakes St. Lawrence area have revealed that permanent settlements started to occur about 6000 BP.
The most significant recorded find is known as the Withrow Site.
It was discovered in 1886 during road building just east of Riverdale Park.
It contained human remains and other artifacts dating back to about 5000 years BP.

Wendat longhouse villages were developed along the river starting in the 1300s when corn became a staple food.

In the 1700s, Mississaugas moved into the region, seeing the Haudenosaunee withdraw south of Lake Ontario.

1787 saw the problematic “Toronto Purchase.”
Believing the purchase to be a rental of the area, and not the release of their rights to the land, the Mississaugas surrendered most of the land that would become York, and then Toronto, to the British.
 
In 1788, Alexander Aitkin, an English surveyor who worked in southern Ontario, referred to the Don River as Ne cheng qua kekonk.
Elizabeth Simcoe, wife of Lieutenant Governor John Graves Simcoe, reported in her diary that another name used was Wonscotanach.
 This is an Anishnaabe phrase meaning the river coming from the back burnt grounds which could refer to an earlier forest fire in the poplar plains to the north.
The name Don River was given by Lt.
Gov. Simcoe because the wide valley reminded him of the River Don in Yorkshire, England.

After the founding of York in 1793, several mills were constructed along the lower Don.
One of the first was at Todmorden Mills.
These mills initially turned out lumber, flour and paper products.
By the 1850s, there were more than 50 mills along the Don and its tributaries.
The Lower Don was becoming an industrial setting.
Petroleum storage facilities, poultry and pork processing plants were constructed along the banks of the Don.
In 1879, the Don Valley Brick Works opened.
Polluted effluent from these factories and the growing city nearby was turning the Don and its marshy mouth into a polluted hazard.

There were two prominent hills that were north of Bloor.
Sugar Loaf Hill at Bloor Street was a conical hill removed during the construction of the Prince Edward Viaduct (commonly referred to as the Bloor Viaduct).
Tumper's Hill, near Don Mills Road, was flattened in the 1960s during the construction of the Don Valley Parkway.

In the 1880s, the lower part of the Don south of the former Winchester Street bridge was straightened (east of the original mouth) and placed in a channel to create additional harbour space and industrial dock space for boats.
Known as The Don Improvement Project, the straightened river was also supposed to divert the polluted waters into the Ashbridges Bay marsh.
This proved unsuccessful so the mouth was turned 90 degrees west where it empties into the inner harbour.
This short extension of the harbour is known as the Keating Channel.
The channel north of Lake Shore Blvd.
East ceased being navigable when the Gardiner Expressway was constructed in the 1950s.
Boats may still enter the Keating Channel by going underneath a lift bridge at Cherry Street.

During the early part of the 20th century the river and the valley continued to be neglected.
31 separate sewage treatment facilities were built along the river.
Over 20 sites in the valley and adjacent ravines were used as landfills for garbage and industrial refuse.
In 1917, the Don Destructor was built beside the river, just north of Dundas Street East.
The incinerator operated for 52 years, burning about 50,000 tonnes of rubbish annually.

In 1946, a plan by the Shirriff company to demolish pioneer dwellings in the area of Todmorden Mills led outraged citizens to form the Don Valley Conservation Association volunteer organization.
The Association's opposition was successful in causing Shirriff to abandon the project in 1947.
The Association continued its activities, planting tree seedlings, stopped the picking of wild flowers, particularly
Humans first arrived in the Don River area approximately 12,500 years BP, most likely as nomadic hunters. While there is little archaeological evidence in the Don valley itself, regional finds in the Great Lakes St. Lawrence area have revealed that permanent settlements started to occur about 6000 BP. The most significant recorded find is known as the Withrow Site. It was discovered in 1886 during road building just east of Riverdale Park. It contained human remains and other artifacts dating back to about 5000 years BP.
Wendat longhouse villages were developed along the river starting in the 1300s when corn became a staple food.
In the 1700s, Mississaugas moved into the region, seeing the Haudenosaunee withdraw south of Lake Ontario.
1787 saw the problematic “Toronto Purchase.” Believing the purchase to be a rental of the area, and not the release of their rights to the land, the Mississaugas surrendered most of the land that would become York, and then Toronto, to the British.  
In 1788, Alexander Aitkin, an English surveyor who worked in southern Ontario, referred to the Don River as Ne cheng qua kekonk. Elizabeth Simcoe, wife of Lieutenant Governor John Graves Simcoe, reported in her diary that another name used was Wonscotanach.  This is an Anishnaabe phrase meaning the river coming from the back burnt grounds which could refer to an earlier forest fire in the poplar plains to the north. The name Don River was given by Lt. Gov. Simcoe because the wide valley reminded him of the River Don in Yorkshire, England.
After the founding of York in 1793, several mills were constructed along the lower Don. One of the first was at Todmorden Mills. These mills initially turned out lumber, flour and paper products. By the 1850s, there were more than 50 mills along the Don and its tributaries. The Lower Don was becoming an industrial setting. Petroleum storage facilities, poultry and pork processing plants were constructed along the banks of the Don. In 1879, the Don Valley Brick Works opened. Polluted effluent from these factories and the growing city nearby was turning the Don and its marshy mouth into a polluted hazard.
There were two prominent hills that were north of Bloor. Sugar Loaf Hill at Bloor Street was a conical hill removed during the construction of the Prince Edward Viaduct (commonly referred to as the Bloor Viaduct). Tumper's Hill, near Don Mills Road, was flattened in the 1960s during the construction of the Don Valley Parkway.
In the 1880s, the lower part of the Don south of the former Winchester Street bridge was straightened (east of the original mouth) and placed in a channel to create additional harbour space and industrial dock space for boats. Known as The Don Improvement Project, the straightened river was also supposed to divert the polluted waters into the Ashbridges Bay marsh. This proved unsuccessful so the mouth was turned 90 degrees west where it empties into the inner harbour. This short extension of the harbour is known as the Keating Channel. The channel north of Lake Shore Blvd. East ceased being navigable when the Gardiner Expressway was constructed in the 1950s. Boats may still enter the Keating Channel by going underneath a lift bridge at Cherry Street.
During the early part of the 20th century the river and the valley continued to be neglected. 31 separate sewage treatment facilities were built along the river. Over 20 sites in the valley and adjacent ravines were used as landfills for garbage and industrial refuse. In 1917, the Don Destructor was built beside the river, just north of Dundas Street East. The incinerator operated for 52 years, burning about 50,000 tonnes of rubbish annually.
In 1946, a plan by the Shirriff company to demolish pioneer dwellings in the area of Todmorden Mills led outraged citizens to form the Don Valley Conservation Association volunteer organization. The Association's opposition was successful in causing Shirriff to abandon the project in 1947. The Association continued its activities, planting tree seedlings, stopped the picking of wild flowers, particularly 
Don River (Ontario)