Question: Which one of the two landmarks between which Rocky Mountain Trench stretches that is a large natural freshwater lake west of the Mississippi River?
Sentence (from "Rocky Mountain Trench"): It is both visually and cartographically a striking physiographic feature extending approximately 1600 km from Flathead Lake, Montana to the Liard River, just south of the British Columbia-Yukon border near Watson Lake, Yukon.
Relevant evidence: Yes