According to Alexander Caulfield Anderson's map, Rat Lake is located above Rivière à la Grise and to the eastern side of the Okanogan River. However it is unclear if this is the correct location as there is another known
Rat Lake which is situated in almost the same location except that it is situated
the westernside of the Okanogan River.1 It is unknown whether Anderson misrepresented the lake or if there are two Rat Lakes.
Rat Lake of the Okanogan Country, Washington State, is located just up from the town
of Brewster and is known as a great fishing lake; as well as, one of the better ice fishing lakes in the Okanogan.2