Hoggs Hollow is one of the most affluent neighbourhoods in Toronto, Ontario, Canada, located in the Don River Valley and centred on the intersection of Yonge Street and York Mills Road/Wilson Avenue.
Hoggs Hollow is named after Joseph Hogg, a Scotsman who settled in the area in 1824. Hogg operated a whisky distillery and a grist mill, and was viewed as the most successful of all the millers in the valley. The name is usually written without the apostrophe as Hoggs Hollow, but sometimes appears as Hogg's Hollow.
In 1856, John and William Hogg, sons to James Hogg, subdivided their father's estate under the name "Hoggs Hollow". The Hoggs Hollow subdivision included one hundred and forty-one lots. With the area full of quick sand, swamps and bogs, only a few houses were actually built at this time, however. the subdivision stood in close proximity to the historic village of York Mills. A school, post office, pottery, blacksmith, livery, stable, store, golf links and clubhouse, hillside cemetery (at Yonge Street and Mill Street) and St. John's Anglican Church served the community, one largely made up of Scottish, Irish and English immigrants.
Subdivision of the present day Hoggs Hollow neighbourhood began in the 1920s with the creation of lots, layout of roads, and design of homes reflecting the aesthetic of the English countryside. In 1925, a two-room elementary schoolhouse named the Baron Renfrew School opened to replace an earlier structure at 45 York Mills Road (formerly Mercer Avenue and/or concession road 19) that was destroyed by fire.
In 1929, the Loretto Sisters Institute of the Blessed Virgin Mary moved their Motherhouse and Loretto Abbey Catholic Secondary School to the area.
The neighbourhood grew in stages and was finally completed in the 1960s. Both St. John's Anglican Church and Baron Renfrew (renamed York Mills Public School) grew in size with various additions added. Agricola Finnish Lutheran Church was built in 1967, serving Toronto and area's Finnish Lutheran community.
In 1892, the Metropolitan Street Railway extended streetcar service along Yonge Street from Toronto (Summerhill) to the southern rim of Hoggs Hollow near today's Glen Echo Road, and then through the valley to Richmond Hill in 1897. This radial railway service through the valley ended in 1948. However, the Yonge streetcar line continued to operate southbound service from Glen Echo Road until 1954. Since 1973, Hoggs Hollow has been served by the York Mills subway station.
In 1982, York Mills Public School was decommissioned and renovated as office space for the Metro Toronto school board (used until 1998). The historic two room schoolhouse exterior was restored. The school was demolished in 2004 with bricks used to create a memorial.
Hoggs Hollow was a part of the City of North York until 1998 when that city merged with five other municipalities and a regional government to form the new "City of Toronto".
The Miller Tavern (formerly the Jolly Miller Tavern), c. 1857, located at the bottom of Hoggs Hollow Hill, 3885 Yonge Street, was closed for many years, but re-opened in 2004 after many battles between developers, the city and groups that wanted to preserve the historical landmark. The George S. Pratt House, c. 1886, located at 17 Mill Street, is another historic landmark in Hoggs Hollow. In need of funds, The York Mills Public School building was sold by the school board and demolished. Many of the original estate homes and modern movement residences of the early to mid-20th century are being demolished in favour of large new homes. With a densely developed business area, many businesses and services are available, and while church attendance has diminished at St. John's, other churches and synagogues now serve the people of the area.
On October 15, 1954, the valley was inundated by Hurricane Hazel and many attempts have since been made to manage water in the natural watershed of a valley though many homes are still prone to moisture and flooding from the watertable. A steel truss bridge crossing Yonge Street at York Mills Road was damaged and replaced by a temporary bailey bridge.
On March 17, 1960, the incident popularly known as the "Hoggs Hollow Disaster" occurred. Five young Italian immigrant workers were killed while constructing a tunnel for a water main at Hoggs Hollow. The details of the accident, where they were trapped 35 feet underground in a cramped, dimly lit tunnel, sparked a public outcry over the lack of safety standards in construction. Ultimately it led to an improvement in working conditions. 
Periodically, attempts have been made to connect back portions of the valley with new roads to the higher set neighbourhoods of the ridges above.