Ramsey Lake

Where Ramsey Lake is

Ramsey Lake lies in the District of Sudbury, within the City of Greater Sudbury.

How deep is Ramsey Lake?

Ramsey Lake reaches a maximum recorded depth of 25.4 meters, determined from 26,445 soundings taken during Ontario’s 2005 survey.

See also Ontario's Largest and Deepest Lakes

Surveyed Depths

Ontario has surveyed the depths of several thousand of its lakes over more than half a century. Later surveys were conducted by boat with satellite positioning and produced hundreds of thousands of soundings per lake. Earlier surveys were charted by running transects across the water and drawing depth contours by hand.

Water quality

Ontario’s Lake Partner Program is a volunteer monitoring network. Participants collect water samples for phosphorus analysis and measure water clarity through the summer with a Secchi disk. Most sites are sampled for phosphorus once a year, in spring, and some several times a year between spring and fall. Phosphorus in many lakes rises through the summer, so the two kinds of average are measured on different bases.

Phosphorus is the nutrient that controls how much algae a lake can grow. A lake with little phosphorus stays clear and supports cold-water fish such as lake trout. As phosphorus rises, algae increase, the water clouds, and oxygen in the deep water falls as the algae decay. The province classifies each monitoring site by its average phosphorus:

• Oligotrophic, below 10 micrograms per litre: clear water and low algae.
• Mesotrophic, from 10 to 20: moderately productive water, with more algae and weed growth than an oligotrophic lake but rarely a bloom.
• Eutrophic, above 20: nutrient-rich water, prone to algal blooms and low oxygen at depth.

Ramsey Lake has 6 Lake Partner monitoring sites. Four have reported phosphorus for the three or more years the province requires before a status is assigned. One of those sites is classified oligotrophic and three mesotrophic.

The longest record is held by site 4534/4 at City of Sudbury 4 E, with phosphorus sampled once a year over 13 years to 2025. Its long-term mean phosphorus concentration is 10.12 micrograms per litre, within the mesotrophic band, which runs from 10 to 20.

A Secchi disk is a white or black-and-white plate lowered on a marked line until it disappears from view. The depth at which it vanishes is the Secchi depth, a direct measure of water clarity. Clearer water gives a deeper reading.

The 1 clarity readings at site 4534/4 give a median Secchi depth of 3.0 meters.

See also Lake Water Quality and Blue-Green Algae in Ontario

Ramsey Lake Weather

The weather page for Ramsey Lake carries the forecast over the water, wave heights across the lake, and the modelled water temperature.

Ramsey Lake weather

Water temperature

Ontario’s aquatic resource records class Ramsey Lake as a cold-water lake, with a mean depth of 9.3 meters against its maximum of 25.4.

A lake separates into layers through the summer where it is deep enough. Sunlight and wind warm and mix the upper few meters, and beneath a band of rapid cooling, the thermocline, the water stays cold. A shallow lake mixes to the bottom instead and warms through, sooner in spring and later into autumn.

No provincial monitoring station records water temperature on Ramsey Lake. The LastLake model computes the temperature of its surface water for each day from the daily mean air temperature at Environment Canada’s Sudbury A climate station, 21 kilometers from the lake, or the next nearest station when its record is incomplete, and from the lake’s area of 796 hectares and its mean depth of 9.3 meters.

Each day’s figure carries the model’s typical error for that month on lakes of the same size. The figure in the chart below is the temperature near the surface, away from the shoreline. Bays, shallows and water deeper below the surface differ in temperature. Temperature is not measured when ice covers the lake. The weather page for Ramsey Lake carries the model’s figures for the past weeks and the coming week.

See also Lake Water Temperature in Ontario

Fish in Ramsey Lake

Ontario’s aquatic resource records name 16 fish species in Ramsey Lake. The province’s other records for the lake name one further species, cisco. It appears in the records below.

Popular species in the province’s records

• Lake Trouttrout and whitefish
• Brook Trouttrout and whitefish
• Rainbow Trouttrout and whitefish
• Northern Pikepike
• Walleyeperch
• Yellow Perchperch
• Smallmouth Basssunfish
• Black Crappiesunfish
• Rock Basssunfish
• Pumpkinseedsunfish
• Burbotcod
• Brown Bullheadcatfish

Spawning areas

Ontario maps 7 fish spawning records within the Ramsey Lake outline, for two different species, and all of them are mapped below. Every record is recorded as verified and presently suitable, and none is classed as sensitive.

By number of records

By area mapped

• Walleye6 areas4.5 ha
• Northern Pike1 area13.1 ha

The federal Fisheries Act prohibits the harmful alteration, disruption or destruction of fish habitat without an authorization, so a dock, dredging, infill or shoreline work at a mapped spawning area is reviewed on that basis.

Stocking history

Ontario’s stocking records for Ramsey Lake run from 1946 to 2015 and hold 39 releases. Walleye account for most of the fish: 702,997 released in twenty of the years between 1976 and 2015. The last recorded release was 21,791 walleye frys in 2015.

Eating the fish

The 2026 Guide to Eating Ontario Fish carries consumption advice for nine species taken from Ramsey Lake, tested for contaminants at a sampling location in McKim & Neelon Twps., Sudbury Dist. Each figure below is the most meals a month the guide advises for a fish of that length. Where mercury sets the advice, the figure falls as the fish gets longer, because mercury accumulates over a fish’s life. A zero means the guide advises no meals of that fish at that size.

General population: adultsSensitive population: children under fifteen, women who are or may become pregnant

Fisheries Management Zone 10

Ramsey Lake lies in Fisheries Management Zone 10. Ontario sets its fishing seasons and catch limits by zone.

Fisheries management zones around Ramsey Lake

Where a row reads zone-wide, the zone’s own season or limit above applies.

See also Fishing Seasons in Ontario, Zone by Zone and Fish Stocking in Ontario Lakes

Ramsey Lake Ice Fishing

An ice hut on Ramsey Lake must be removed by March 31. The province sets dates for ice hut removal as a safety measure to ensure huts are removed before thawing occurs. One date applies to an entire fisheries management zone (FMZ). Ramsey Lake lies within FMZ 10.

An ice hut must also be removed before the ice breaks up, whether or not that date has passed. The deadline clears huts from the ice ahead of the thaw and does not close the fishing season.

Registration is required in FMZ 10 for an ice hut built of anything other than fabric, and for a fabric tent covering seven square meters or more. Registration is free, and the number is displayed on the outside of the hut.

Ice In / Out Date

Ice has been recorded on Ramsey Lake in 47 winters between 1939 and 1986. The median date of complete ice cover is December 7 and the median date of complete ice loss is April 27, a median season of 140 days.

The longest recorded season is 158 days in 1959-60, and the shortest is 113 days in 1946-47.

Averaged twenty winters at a time, the date of complete ice cover has barely moved: December 9 in the winters from 1940, and December 7 in those from 1960. Across the same two blocks the average season has gone from 136 days to 144.

Ice in to ice out by winter on Ramsey Lake

The record was contributed by W. R. Skinner, Environment Canada to the Global Lake and River Ice Phenology Database, and the ice was read at a weather station rather than from the middle of the lake. Observations were last contributed for 1986, and none have been added since.

Ice conditions

No public record reports the thickness or the condition of the ice on Ramsey Lake on any given day. Ontario publishes ice safety guidance for anyone going out on the ice, at ontario.ca.

See also Lake Ice in Ontario and When the Lakes Will Freeze This Winter

Getting on the water

Two access marks are mapped on Ramsey Lake.

See also Boat Launches on Ontario Lakes

Islands and names

Ramsey Lake contains seventeen islands in the Ontario Hydro Network’s outline, zero of them over 10 hectares and seven under a tenth of a hectare.

Official names

Ontario’s geographic names register lists 18 official names on the water and its islands: 12 islands and four bays.

Bays 4

• CPR Bay
• Frenchman's Bay
• Hermit's Bay
• South Bay

Communities on the lake 3

• Sudbury
• Bell Grove
• Minnow Lake

Nearby lakes

• Nepahwin Lake3 km away
• Richard Lake5 km away
• Long Lake17 km away
• Nepewassi Lake27 km away

All lakes

Questions about Ramsey Lake

• How deep is Ramsey Lake?

  Its maximum recorded depth is 25.4 meters, determined during Ontario’s 2005 survey.

• How big is Ramsey Lake?

  Its surface covers 8.0 square kilometers and it holds 17 islands. Of its 34 kilometers of shoreline, 29 kilometers is the mainland shore and 5 kilometers is the shore of the islands.

• What fish are in Ramsey Lake?

  Ontario’s aquatic resource records name sixteen species, among them lake trout, walleye, smallmouth bass, northern pike, yellow perch and black crappie. The lake’s spawning, consumption and stocking records also name cisco.

• Is there a public boat launch?

  No boat launch on Ramsey Lake is marked in the records this page draws on.