John Scarlett (1777–1865) was a merchant-miller who played a significant role in the development of the part of the historic York Township that later became the Junction neighbourhood of Toronto, Ontario.

[2] In 1809 he started work as chief clerk in the inspector general's office in York, a position he held for 20 years.

[8] John Scarlett is most notable as a land owner and entrepreneur who made a significant contribution to the early economy of Toronto and York Township.

He began acquiring property in York Township shortly after his arrival beginning in 1809 when he purchased 33 acres along the Humber River from Thomas Cooper including a mill site.

Though surveyors were supposed to reserve mill sites for the crown in practice over 60 years almost all of them were privately owned on operated.

[6] Like other mill owners along the Humber River such as Thomas Fisher and William Gamble, Scarlett was not simply a miller who took money or a cut of produce for sawing wood or grinding grain, rather he ran a mill complex which operated as a general store, commercial hub and a grain exchange.

Scarlett would buy customers' grain or lumber or exchange it for other goods and then transport it into town, a task which was difficult for a typical producer.

He was for a long time (excepting the farmers) the only employer of labour in the neighbourhood, he having extensive brick yards on Dundas street, near the Plank road, and was besides the first owner of nearly all the land in the vicinity.Scarlett was one of the incorporators of the Bank of Upper Canada.

In 1836 he pulled his eldest son Edward Christopher form his studies at Upper Canada College to teach him how to run a mill.

In 1836-1837 he, Edward Christopher and son John Archibald took a trip to the United States midwest to study milling equipment.

Changes in colonial trade laws,[15] the decline of timber resources in the Humber Valley and continued destruction from flooding spelled an end to the prosperity of millers shortly thereafter.

The following year the Scarlett family moved from Simcoe Grange to a new larger house at what is now the north side of the intersection of Dundas Street and Runnymede Rd.

[17] Later, in the 1880s, as the area was subdivided and developed the name Runnymede started to be used for local schools, churches, a hospital, theater etc.

[20][21] Scarlett loved horses and was a hard rider even up to an advanced age but never owned a racehorse and probably never placed a bet.