Provincial Watersheds, Historical

Note: This data has been replaced by the Ontario Watershed Boundaries (OWB). We are no longer updating this data. It is best suited for historical research and analysis.

A watershed, also known as a catchment basin, includes all land that is drained by a watercourse and its tributaries.

Watersheds are split into four categories:

  • primary
  • secondary
  • tertiary
  • quaternary

These divisions are based on the federal framework originally known as the Water Resources Index Inventory Filing System.

Ontario has 3 primary watersheds:

  • Great Lakes – St. Lawrence
  • Southwestern Hudson Bay
  • Nelson River

Secondary watersheds are subdivisions of primary watersheds in Ontario. Most secondary divisions are either large river systems or groupings of small coastal streams.

Tertiary watersheds are subdivisions of secondary watersheds in Ontario.

Quaternary watersheds are subdivisions of tertiary watersheds. There are more than 1000 quaternary watersheds in Ontario.

Ministry contact: Provincial Mapping Unit

Additional information

Tags
Geographic coverage
Ontario
Geography Breakdown
Watershed
Maintainer
Provincial Mapping Unit
Author
Provincial Mapping Unit
Maintainer branch
Mapping and Information Resources Branch
Last Validated Date
June 7, 2021
Update frequency
Never

Provincial Watersheds, Historical

Learn more about accessing data using different formats.

Date range: January 1, 2010 - March 1, 2015

  • ZIP
    Watershed, Primary (Shapefile) | Bassins versants primaires (Fichier de formes) English [9.2 MiB]

    Last Updated: December 17, 2015

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  • ZIP
    Watershed, Primary (File Geodatabase) | Bassins versants primaires (Géodatabase fichier) English [3.2 MiB]

    Last Updated: December 17, 2015

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  • ZIP
    Watershed, Secondary (Shapefile) | Bassins versants secondaires (Fichier de formes) English [21 MiB]

    Last Updated: December 17, 2015

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  • ZIP
    Watershed, Secondary (File Geodatabase) | Bassins versants secondaires (Géodatabase fichier) English [5.9 MiB]

    Last Updated: December 17, 2015

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  • ZIP
    Watershed, Tertiary (Shapefile) | Bassins versants tertiaires (Fichier de formes) English [64.8 MiB]

    Last Updated: December 17, 2015

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  • ZIP
    Watershed, Tertiary (File Geodatabase | Bassins versants tertiaires (Géodatabase fichier) English

    Last Updated: December 17, 2015

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  • ZIP
    Quaternary watershed boundaries (Shapefile) | Limites des bassins hydrographiques quaternaires (Fichier de formes) English

    Last Updated: December 17, 2015

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  • ZIP
    Quaternary watershed boundaries (File Geodatabase) | Limites des bassins hydrographiques quaternaires (Géodatabase fichier) English

    Last Updated: December 17, 2015

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  • ZIP
    Far North Quaternary Watersheds (Shapefile) | Bassins hydrographiques quaternaires du Grand Nord (Fichier de formes) English

    Last Updated: December 17, 2015

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  • ZIP
    Far North Quaternary Watersheds (File Geodatabase) | Bassins hydrographiques quaternaires du Grand Nord (Géodatabase fichier) English

    Last Updated: December 17, 2015

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Supporting Files

  • PDF
    Watershed - User Guide English [528.5 KiB]

    Last Updated: May 20, 2015

    This highly specialized publication is available in English only in...

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