Castle Frank Brook is a buried

Subterranean river

A subterranean river is a river that runs wholly or partly beneath the ground surface – one where the riverbed does not represent the surface of the Earth ....

 creek

Urban stream

An urban stream is a formerly natural waterway that flows through a heavily populated area. Urban streams are often significantly polluted, due to urban runoff and combined sewer outflows....

 and south-west flowing tributary of the Don River in central and north-western Toronto

Toronto

Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...

, Ontario

Ontario

Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, originating near the intersection of Lawrence Avenue

Lawrence Avenue

Lawrence Avenue is a major east-west thoroughfare in Toronto, Ontario, Canada. It is divided into east and west portions by Yonge Street, the dividing line of east-west streets in Toronto....

 and Dufferin Street

Dufferin Street

Dufferin Street is a major north-south street in Toronto, Ontario, Canada. It is a concession road, two concessions west of Yonge Street. The street starts at the foot of Lake Ontario, continues north to Toronto's northern boundary with some discontinuities and continues into York Region where it...

.

Residential and industrial development in the former suburban cities of York

York, Ontario

York is a dissolved municipality in Toronto, Ontario, Canada. Geographically, it is located northwest of Old Toronto, southwest of North York and east of Etobicoke, where it is bounded by the Humber River. Formerly a separate city, it was one of six municipalities that amalgamated in 1998 to form...

 and North York have obliterated nearly all traces of its original course and topography in the uppermost reaches, but the original stream valley is evident in several older districts bordering the lower reaches. Sections of the lower valley include Cedarvale Park ravine

Cedarvale Park (Toronto)

Cedarvale Park is a park located in Toronto, Ontario, Canada. It is bordered by very steep hills, and is located in the Cedarvale neighbourhood of Toronto. The Spadina subway line tunnels underneath it, between St. Clair West and Eglinton West stations...

, the Nordheimer Ravine near the intersection of St. Clair Avenue

St. Clair Avenue

St. Clair Avenue is a major east-west street in Toronto, Ontario, Canada. It was laid out in the late 18th century by the British as a concession road , north of Bloor Street and north of Queen Street....

 and Spadina Road, and the Rosedale Ravine just above the brook's confluence with the Don. Short segments of the creek are exposed in Cedarvale Park and the lower Rosedale Valley. The southern section of Vaughan Road

Vaughan Road

Vaughan Road is a road in Toronto, Ontario, Canada. It is a contour collector road that is parallel to a buried creek to the north called Castle Frank Brook. Vaughan Road begins on Bathurst Street south of St. Clair Avenue West, then it becomes a north-south street, hence its address numbering...

 roughly parallels the brook's course, bypassing the steep slopes of the Cedarvale ravine. The brook's topographic influence is still evident at Ramsden Park, to the north of the intersection of Avenue Road and Davenport Road, representing the boundary of the densely developed Yorkville

Yorkville, Toronto

Yorkville is a district in Toronto, Ontario, Canada, well known for its shopping. It is a former village, annexed by the City of Toronto. It is roughly bounded by Bloor Street to the south, Davenport Road to the north, Yonge Street to the east and Avenue Road to the west, and is considered part of...

 district. The Toronto Transit Commission

Toronto Transit Commission

-Island Ferry:The ferry service to the Toronto Islands was operated by the TTC from 1927 until 1962, when it was transferred to the Metro Parks and Culture department. Since 1998, the ferry service is run by Toronto Parks and Recreation.-Gray Coach:...

's Spadina subway line

Toronto subway and RT

The Toronto subway and RT is a rapid transit system in Toronto, Ontario, Canada, consisting of both underground and elevated railway lines, operated by the Toronto Transit Commission . It was Canada's first completed subway system, with the first line being built under Yonge Street, which opened in...

 follows the path of the creek from Eglinton West station

Eglinton West (TTC)

Eglinton West is a station on the Yonge–University–Spadina line of the subway system in Toronto, Ontario, Canada. It is located on Allen Road/Everden Road at 1300 Eglinton Avenue West....

 to St. Clair West station

St. Clair West (TTC)

St. Clair West is a station on the Yonge–University–Spadina line of the subway system in Toronto, Ontario, Canada. It is at 370 St. Clair Avenue West between Bathurst Street and Tweedsmuir Avenue. The sports field of St. Michael's College School is directly above the length of the station; a...

, finally deviating southward at Spadina Road.

The brook is named for the summer residence of Ontario's first colonial governor, John Graves Simcoe

John Graves Simcoe

John Graves Simcoe was a British army officer and the first Lieutenant Governor of Upper Canada from 1791–1796. Then frontier, this was modern-day southern Ontario and the watersheds of Georgian Bay and Lake Superior...

, which in turn was named for Simcoe's son, Francis Gwillim. It was built either on the west side of the Don River near the modern Prince Edward (Bloor) Viaduct

Prince Edward Viaduct

The Prince Edward Viaduct System, commonly referred to as the Bloor Viaduct or the viaduct, is the name of a truss arch bridge system in Toronto, Ontario, Canada that connects Bloor Street East, on the west side of the system, with Danforth Avenue on the east...

, or on the east side of Cabbagetown

Cabbagetown, Toronto

Cabbagetown is a neighbourhood located on the east side of downtown Toronto, Ontario, Canada. It comprises "the largest continuous area of preserved Victorian housing in all of North America", according to the Cabbagetown Preservation Association....

 near the river. The home featured a façade in the Georgian architectural

Georgian architecture

Georgian architecture is the name given in most English-speaking countries to the set of architectural styles current between 1720 and 1840. It is eponymous for the first four British monarchs of the House of Hanover—George I of Great Britain, George II of Great Britain, George III of the United...

 style. It was abandoned when Simcoe returned to England in 1794, and burned down in 1829. Castle Frank subway station

Castle Frank (TTC)

Castle Frank is a station on the Bloor–Danforth line of the subway system in Toronto, Canada. It is located at 600 Bloor Street East at Castle Frank Road, near the former location of Viaduct streetcar loop, which was the longtime terminus of the Parliament streetcar.-Entrances:*The main entrance to...

 takes its name from the former residence. A second home of the same name was built north of this site by Sir Edward Kemp. It was demolished in 1962 for the current Rosedale Heights School of the Arts

Rosedale Heights School of the Arts

Rosedale Heights School of the Arts is an arts-based high school in downtown Toronto. Formerly Castle Frank, the school has been reinvented and re-purposed by Principal Barrie Sketchley...

. The site of the original summer home can be seen from aerial photos as a partially cleared area with a ring-like shape.