Big Rideau Lake
lake in Ontario, Canada
Big Rideau Lake is a lake in the municipalities of Tay Valley and Drummond/North Elmsley, Lanark County and Rideau Lakes, United Counties of Leeds and Grenville in Eastern Ontario, Canada. The lake is on the border between the two counties, 72 kilometres (45 mi) to the southwest of Ottawa. It is 32 kilometres (20 mi) long and is 6 kilometres (3.7 mi) wide, is much narrower at its northeastern end than at its southwestern end, and is part of the Saint Lawrence River drainage basin. It is the largest lake on the Rideau Canal, which was designated a UNESCO world heritage site in 2007.
Hydrology
The primary inflow, at the southwest, is the Rideau River/Rideau Canal from Upper Rideau Lake via The Narrows channel and the Narrows lock and control structures. A second primary inflow is Black Creek at the west. The primary outflow, at the north, is also the Rideau River/Rideau Canal which leads via a channel to Lower Rideau Lake. The Rideau River and Canal flow to the Ottawa River and then to the Saint Lawrence River.
Settlements
The small community of Rideau Ferry is located at the junction between the Big Rideau and Lower Rideau Lake, at the northeastern end of the lake. The community of Portland is located along the southern shore of the lake.
This brief starts where responsible research should: with the source description of “Big Rideau Lake” as lake in Ontario, Canada. Everything that follows is an evidence route, not borrowed authority.
Why this record matters
The subject matters to the places & architecture register because the source frames it as lake in Ontario, Canada. Its deeper value depends on whether names, dates, institutions and citations support that framing.
Maps, plans, fabric surveys and administrative records can establish how the site’s name, extent and function changed over time. The source revision retrieved here is dated Aug 30, 2026. The linked authority identifier is Q3113637. Authority coordinates are 44.750, -76.233. 1 of 1 selected statements include explicit references; 0 carry qualifiers and 0 use preferred rank. The first chronological checks are 2007.
Architectural summaries often privilege surviving fabric and can understate demolished phases, contested use or displaced communities. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Treat names, boundaries and functions as historically changeable. Maps, plans, inventories and administrative records can clarify what the place meant at different dates.
- Historic place names
- Jurisdictional context
- Routes into maps and plans
Contemporary maps, plans, listed-building records, estate papers and the responsible local or national archive.
Three-step research path
- Establish the record: confirm the title “Big Rideau Lake”, its source revision and the description used here.
- Expand the search: follow Big Rideau Lake primary sources, Big Rideau Lake archive and Rideau research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Big Rideau Lake”?
- Which authority defined the place, boundary or structure at the relevant date?
- What physical evidence or contemporary plan supports the description?
Search terms from this dossier
This entry incorporates text from “Big Rideau Lake” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.