White Cap Mountain rises in western Maine’s Franklin County about one mile east of the Canada–US border with Quebec, in a remote upland area near the headwaters of the Androscoggin system. Near Kennebago Divide Mountain, it stands within the upper Androscoggin watershed, whose waters ultimately flow to Merrymeeting Bay and the Gulf of Maine. Its north face drains into the Kennebago River, then through Cupsuptic Lake and connected lakes to the Rapid River and Umbagog Lake, the Androscoggin’s source. Its southeastern and southwestern slopes drain into Bear Brook and Porter Brook, tying the mountain closely to the borderland’s intricate network of waterways.