The Tualatin Mountains (also known as the West Hills or Southwest Hills of Portland) are a range on the western border of Multnomah County, Oregon, United States. A spur of the Northern Oregon Coast Range, they separate the Tualatin Basin of Washington County, Oregon, from the Portland Basin of western Multnomah County and Clark County, Washington. The highest peak in the range is Dixie Mountain at 1,609 feet (490 m). Other notable peaks include Cornell Mountain at 1,270 feet (390m), Council Crest at 1,073 feet (327 m), and Pittock Hill, location of the Pittock Mansion.