Quick Facts

The Oak Ridges Moraine is a landform unique to southern Ontario. One of Ontario’s largest moraines, the Oak Ridges Moraine extends 160 kilometres from the Niagara Escarpment in the west to the Trent River system in the east, and is on average 13 kilometers wide. Below are more quick facts about the Oak Ridges Moraine. 

Quick Facts about the Oak Ridges Moraine

  • The Moraine stretches 160 kilometers from just east of Mono Mills at the Niagara Escarpment to Castleton, north east of Cobourg
  • North and south the Moraine is ‘narrowest’ ( < ½ km ) at Bewedley on the west end of Rice Lake and (just about ½ km) at Simcoe Street north of Oshawa. An area of major concern for connectivity of the Moraine occurs within Richmond Hill at Yonge Street where the only undeveloped ‘natural linkage area’ is considerably less than ½ km in the area currently referred to as Corridor Park
  • The Moraine covers a geographic area of 1,900 square kilometers (734 sq mi) approximately 1/3 of the size of Prince Edward Island!
  • 64 rivers or streams begin on the Moraine and run either south directly into Lake Ontario, or north to Lakes Scugog, Simcoe or Georgian Bay (Lake Huron). Some of these watercourses include The Credit, Humber, Don, Rouge, Ganaraska, Pigeon, Nonquon, Beaverton, Black, Holland (East and West) and Nottawasaga Rivers; Etobicoke, Duffins, Lynde, Oshawa, Bowmanville, Burnley and Innisfil Creeks
  • 90% of the Moraine is in private ownership
  • 60% of the Moraine is in the Greater Toronto Area, (Peel, York and Durham Regions) 20% in Northumberland County, 7% in the City of Kawartha Lakes, 5% in Simcoe County, 3% in Peterborough County and 1% in Dufferin County
  • 32% of the Moraine is covered in upland forests and is one of six recognized areas for forest bird diversity in southern Ontario
  • 5% of the Moraine is wetlands – mostly smaller but very important in their function as headwaters and also as isolated habitat for waterfowl
  • There are 37 kettle lakes and 46 bogs/fens (noteworthy for northern plants and animals)
  • 0.2% of the Moraine is covered with 161 remnant tall grass prairie, sand barrens and oak-pine savannah/woodlands

One-hundred-and-fifty meters deep, the Moraine stands out as one of the most distinct landscapes of southern Ontario. Its height above the flat lands to the north and south, its rolling hills, meandering river, stream valleys and large blocks of mixed forest provide solace and a sense of connection to the people who live, work and play on the Moraine, natural and wild habitat for flora and fauna, and untapped recreational opportunities.

The Moraine has an enormous amount of biodiversity.

There are:

  • 1,171 plant species
  • 125 species of moss
  • 166 breeding bird species (and more through migratory seasons)
  • 30 species of reptiles and amphibians
  • 51 mammal species
  • 73 fish species
  • 74 species of butterflies
  • 70 dragonflies and damselfly species
  • 88 species are provincial or national species at risk and 466 are moraine rare (Canada as a whole has 71,500 species of plants and animals, with approximately 422 species at risk)

There are 72 life and earth science Areas of Natural and Scientific Interest (ANSI’s) covering 15% of the moraine and 82 Environmentally Significant Areas (ESAs) For more information on these, check out:

Politically or jurisdictionally, portions of the Oak Ridges Moraine are located within or include:

  • 32 municipalities (8 upper-tier; region/county and 24 lower-tier; town/township)
  • 9 conservation authorities
  • 16 provincial electoral ridings
  • 15 federal electoral ridings
  • over 500 schools in 10 school boards (plus numerous private schools)
  • over 40 non-government environmental organizations

However, the Oak Ridges Moraine is more than just a beautiful landform feature with its breathtaking vistas, rolling hills, wooded valleys and ‘kettle’ lakes. Its most precious feature lies hidden below the grounds’ surface.

For more information, check out our page about water.