Grand Lake (Nipissing)  Grand Lake is a lake in the Ottawa River drainage basin in the geographic townships of Barron and Stratton in the Unorganized South Part of Nipissing District in Northeastern Ontario, Canada. The lake is long and narrow and lies in an east–west orientation, mostly in Barron Township except for the southeastern end which is in Stratton Township; it is entirely within Algonquin Provincial Park. The primary inflows are the Barron River from its source at Clemow Lake at the west and Carcajou Creek at the large Carcajou Bay at the southeast, and primary outflow is the Barron River, controlled by the Grand Lake Dam, which flows at the east to Stratton Lake and further via the Petawawa River to the Ottawa River. Grand Lake is crossed in the middle by the originally Canadian Northern Railway, later Canadian National Railway, main line, now abandoned. The Achray park campground, formerly a station on the railway, is located on the north shore, and the unincorporated place of Hydro is on the former railway line at the western tip of the lake, near where a Hydro One hydroelectricity transmission line passes.  ""right" and "left" are with reference to the Barron River"