Algoma

• Long Lake (Varley Township, Ontario)
• Long Lake (Albanel Township, Ontario)
• Long Lake (North Shore, Ontario)
• Long Lake (Fontaine Township, Ontario)
• Long Lake (Sampson Township, Ontario)
• Long Lake (Bruyere Township, Ontario)
• Long Lake (Common Township, Ontario)
• Long Lake (Huron Shores, Ontario)

Frontenac County

• Long Lake (South Frontenac, Ontario)
• Long Lake (Central Frontenac, Ontario)

Haliburton County

• Long Lake (Highlands East, Ontario)
• Long Lake (Dysart et al, Ontario)

Kenora

• Long Lake (Pelican Township, Ontario)
• Long Lake (Machin, Ontario)
• Long Lake (Kamungish River)
• Long Lake (Redvers Township, Ontario)
• Long Lake (Wabigoon River)

Manitoulin

• Long Lake (Central Manitoulin, Ontario)
• Long Lake (Northeastern Manitoulin and the Islands, Ontario)

Muskoka

• Long Lake (Bracebridge, Ontario)
• Long Lake (Wood Township, Ontario) (Muskoka Lakes)
• Long Lake (Cardwell Township, Ontario) (Muskoka Lakes)

Nipissing

• Long Lake (Kearney, Nipissing District, Ontario)
  Long Lake (Kearney, Nipissing District, Ontario)
  Long Lake is a lake in the municipality of Kearney in central Ontario, Canada.The lake is located in the part of Kearney located within the territorial district of Nipissing, but is however politically located in Parry Sound District...
  
  
• Long Lake (East Ferris, Ontario)
  Long Lake (East Ferris, Ontario)
  Long Lake is a small lake in northeastern Ontario, Canada. It is located in the municipality of East Ferris in Nipissing District.The lake is about 1.4 km in length and is around 100m in width...
  
  
• Long Lake (Calvin, Ontario)

Parry Sound

• Long Lake (Humphrey Township, Ontario) (Seguin)
• Long Lake (Kearney, Parry Sound District, Ontario)
• Long Lake (Joly, Ontario)
• Long Lake (East Mills Township, Ontario)
• Long Lake (Wilson Township, Ontario)
• Long Lake (Nipissing, Ontario)
• Long Lake (The Archipelago, Ontario)
• Long Lake (Foley Township, Ontario) (Seguin)

Peterborough County

• Long Lake (Douro-Dummer, Ontario)
• Long Lake (Havelock-Belmont-Methuen, Ontario)
• Long Lake (North Kawartha, Ontario)

Renfrew County

• Long Lake (Laurentian Valley, Ontario)
• Long Lake (Greater Madawaska, Ontario)
• Long Lake (Wylie Township, Ontario) (Laurentian Hills)
• Long Lake (Rolph Township, Ontario) (Laurentian Hills)

Sudbury

• Long Lake (Sables-Spanish Rivers, Ontario)
• Long Lake (Sudbury, Ontario) (Greater Sudbury)
• Long Lake (Ermatinger Township, Ontario)
• Long Lake (Capreol, Ontario) (Greater Sudbury)
• Long Lake (Kelly Township, Ontario)
• Long Lake (Turner Township, Ontario)

Timiskaming

• Long Lake (Sharpe Township, Ontario)
• Long Lake (Lorrain Township, Ontario)
• Long Lake (Milner Township, Ontario)
• Long Lake (Lebel Township, Ontario)

Thunder Bay

• Long Lake (Saganagons Lake)
• Long Lake (Laberge Township, Ontario)
• Long Lake (Kashabowie, Ontario)
• Long Lake (Terrace Bay, Ontario)
• Long Lake (Shuniah, Ontario)
• Long Lake (Athelstane Lake)
• Long Lake (Thunder Bay District, Ontario) (Longlac)

Southern Ontario

• Long Lake (Lanark County, Ontario)
  Long Lake (Lanark County, Ontario)
  Long Lake is a lake in eastern Ontario, Canada in the municipality of Tay Valley in Lanark County.The lake is nearly 3 km long and about 600m wide at its widest....
  
  
• Long Lake (Simcoe County, Ontario)
• Long Lake (Leeds and Grenville United Counties, Ontario)
• Long Lake (Kawartha Lakes, Ontario)
• Long Lake (Hastings County, Ontario)