Grindstone Mountain is a mountain summit located in the Icicle Creek Valley in Chelan County of Washington state. Grindstone Mountain is situated west of Leavenworth, within the Alpine Lakes Wilderness, on land managed by Okanogan-Wenatchee National Forest. Grindstone Mountain is the seventh-highest peak in the Chiwaukum Mountains, a subset of the Cascade Range. Its nearest higher neighbor is Ladies Peak, to the north-northwest, and Cape Horn is set to the north. Precipitation runoff from Grindstone drains into Icicle Creek, which is a tributary of the Wenatchee River. Although modest in elevation, relief is significant since Grindstone rises 4,700 feet above Icicle Creek Valley in less than two miles. Grindstone Mountain was named by Albert Hale Sylvester in association with Grindstone Creek, which flows from Sylvester Lake on this mountain's southwest slope. Sylvester found a small grindstone which had fallen from a pack horse fording the creek.