Toronto, Ontario, has been called “Hogtown” (or “Hog town”) since the 1890s. The nickname is probably from the William Davies Company,  a pork processing and packing company that was then prominent.
   
Chicago, Illinois, was called “Hogtown” since at least 1878. Atchison, Kansas, was called “Hogtown” since at least 1885.
   
Toronto’s nickname of “Hogtown” was popularized in 1890, usually in football stories with the rival city of Hamilton. “Hamilton has no use for the products of the Hogtown sties” was printed in the Kingston (ON) Daily News on August 20, 1890. “But few Hamiltonians were there. The park was given up to the Hogtown toughs and well they used it” was printed in The Catholic Record (London, ON)—originally the Hamilton Herald—on August 30, 1890. “Hamilton should stick to its carnival and leave the fair business to Hogtown” was printed in the Brantford (ON) Expositor on October 10, 1890.
   
Other Toronto nicknames include “Big Smoke,” “Broadway North,” “Centre of the Universe,” “Hollywood North,” “Little Apple.” “Muddy York,” “New York of the North,” “New York Run by the Swiss,” “Queen City,” “T-Dot,” “T.O.,” “The Six” and “Toronto the Good.”
   
   
Wikipedia: Toronto 
Toronto is the provincial capital of Ontario and the most populous city in Canada, with a population of 2,731,571 in 2016. Current to 2016, the Toronto census metropolitan area (CMA), of which the majority is within the Greater Toronto Area (GTA), held a population of 5,928,040, making it Canada’s most populous CMA. Toronto is the anchor of an urban agglomeration, known as the Golden Horseshoe in Southern Ontario, located on the northwestern shore of Lake Ontario. A global city, Toronto is a centre of business, finance, arts, and culture, and is recognized as one of the most multicultural and cosmopolitan cities in the world.
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Nickname(s):  “Hogtown”, “The Queen City”, “The Big Smoke”, “Toronto the Good”
     
Wikipedia: Name of Toronto
“Hogtown”, said to be related to the livestock that was processed in Toronto, largely by the city’s largest pork processor and packer, the William Davies Company.
. Possibly derived from the Anglo-Saxon word for York, Eoforwic, which literally translates to “wild boar village”.
. A by-law which imposed a 10-cent-per-pig fine on anyone allowing pigs to run in the street.
 
Wikipedia: William Davies Company
William Davies Company was a pork processing and packing company in Toronto, Ontario, Canada. At one time, it was the largest pork packer in the British Empire, and it operated Canada’s first major chain of food stores. One of Toronto’s longstanding nicknames, “Hogtown”, is attributable to the millions of pigs processed annually by the William Davies Company.
       
6 November 1878, The Gazette (Montreal, Quebec), “Chicago Correspondence,” pg. 4, col. 5:
Mr. B. P. Hutchinson, the great porkpacker, invited the GAZETTE correspondent to visit “Hog-town” the other day, and a seat in his buggy behind his pair of 240 beauties, soon placed me within the territory owned and controlled by the famous Union Stock Yards Company, lying to the south-west of the city limits.
 
28 October 1885, The News (Yates Center, Woodson County, KS), pg. 2, col. 3:
ATCHISON has been supplanted and Iola is now the “Hog-Town” of Kansas.
 
17 July 1890, The Weekly Capital (Topeka, KS), pg. 8, col. 1:
DESERVING ITS NAME AS HOG TOWN.
(Kansas City, MO.—ed.)
 
Newspapers.com
20 August 1890, Kingston (ON) Daily News, “A Gang of Hoodlums,” pg. 1, col. 4:
Referring to the disgraceful conduct of Toronto hoodlums in Hamilton on Toronto’s civic holiday in the News of the Queen city says: ...
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Hamilton has no use for the products of the Hogtown sties.
     
Canadiana.ca
30 August 1890, The Catholic Record (London, ON), “The Product of Orangeism” (Hamilton Herald), pg. 6, col. 3:
But few Hamiltonians were there. The park was given up to the Hogtown toughs and well they used it.
 
Newspapers.com
10 October 1890, Brantford (ON) Expositor, “Editorial Brevities,” pg. 4, col. 4:
Hamilton’s fair this year was a very poor show, so much so that the local press is compelled to admit the corn. Hamilton should stick to its carnival and leave the fair business to Hogtown.
   
Newspapers.com
13 October 1890, The Gazette (Montreal, Quebec), “Gossip from Toronto,” pg. 1, col. 6:
The amenities of intercourse between Toronto and Hamilton were evidenced on Saturday when the football teams of the respective places played at the Ambitious city. Toronto was badly beaten in the play, but not satisfied with this the populace of Hamilton absolutely hissed and bullyragged the Toronto team out of their midst, addressing to them such endearing appellations as “Hogtown toughs” and “Boodlers.”
   
Newspapers.com
1 September 1892, The Daily Standard (St. Catharines, ON), pg. 1, col. 1:
“Toronto is largely Ontario.”—Toronto Evening News. That is brief, but we suggest that it be amended to read “Toronto is Ontario,” which would probably express the sentiments of many of the leading citizens of Hog-town.
 
23 September 1892, The Globe (Toronto, ON), pg. 4, col. 5:
The Woodstock Sentinel-Review has an appreciative article on the Toronto Industrial Exposition. Our generous and level headed contemporary says:—
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This seems more rational than gibing at Toronto as Hog Town, ...
   
1 November 1892, The Globe (Toronto, ON), “Football: Hamilton Opinions of the Match Free Kicks,” pg. 6, col. 1:
The Spectator: (...) But should that team happen to beat Hamilton’s striped aggregation, Hogtown will claim the entire outfit.
 
30 March 1893, The Globe (Toronto, ON), “The Convention at Ottawa,” pg. 4, col. 1:
(From the Ottawa Free Press.—ed.)
“Hogtown, sometimes called Toronto, is certainly no place for Reformers to meet in.”
 
21 June 1893, The Globe (Toronto, ON), pg. 10, col. 2:
Hamilton Herald:—(...)
... Toronto, and now that he is in the game he feels badly to see all the honors going to Hogtown.
     
OCLC WorldCat record
Hogtown, working class Toronto at the turn of the century
Author: Gregory S Kealey
Publisher: Toronto : New Hogtown Press, 1972, t.p. 1974.
Edition/Format:   Print book : English
 
OCLC WorldCat record 
Toronto the good : an album of colonial Hogtown
Author: Gerald Utting
Publisher: Vancouver : Bodima Books ; Toronto : Distributed by Macmillan Co. of Canada, ©1978.
Edition/Format:   Print book : English
   
OCLC WorldCat record
Ville-Reine / Hog Town
Author: Mariel O’Neill-Karch
Publisher: [Toronto] : Départment de français, Université de Toronto, 1985.
Series: In: Vecrire, revue des éstudiants du Départment de franca̧is de l’Universite de Toronto.
Edition/Format:   Print book : French
 
blogTO
How Toronto got the nickname Hogtown 
Chris Bateman
Posted on October 05, 2013
The story generally goes that Toronto was nicknamed Hogtown after the sprawling stock yards of the William Davies Company, one of Canada’s earliest and largest meat packers.
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Toronto’s most popular nickname, however, might not be a product of Davies’ company after all. It turns out Ontario towns had been using the name to insult Toronto long before the city decided to claim the title for itself.
 
“Our friend the hog,” the Globe editorial headline from June 23, 1898 read. “In the smaller cities of the Province when a man wants to say nasty things about Toronto he calls it Hogtown.”
 
“The remark originally had no relation at all to our friend the hog, but was merely intended to convey an impression that the citizens of Toronto were porcine in their tendencies and had their forefeet in anything worth having,” it said.
 
blogTO
How Toronto got its various nicknames
Chris Bateman
Posted on November 15, 2014
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Hogtown
There are two main theories regarding the origin of this popular porcine nickname. The most plausible (to my mind) concerns the stockyards William Davies Company, which was once one of Canada’s largest meat packers. Davies, whose company popularized peameal bacon, processed half a million animals at his Don River plant in 1900. Davies died, ironically, after being kicked by a goat aged 90.
 
An alternative is that “Hogtown” was an insult levied at Toronto because of its tendency to dominate affairs at Queens Park. “In the smaller cities of the Province when a man wants to say nasty things about Toronto he calls it Hogtown,” read a Globe editorial in 1898.
     
Narcity
Toronto Nicknames & Where They Came From: A Tourist’s Guide
Hogtown to the Six.
Zahra Khozema May 15, 2015
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5. Hogtown
“Hogtown” likely comes from the city’s former reputation as home to some of the British Empire’s most renowned bacon and pork manufacturers, Canada’s answer to Cincinnati’s “Porkopolis.” But we know which one is better.