King's Highway 89, commonly referred to as Highway 89, is an east–west provincially maintained highway in the south central portion of the Canadian province of Ontario, stretching 107 kilometres (66 mi) from the junction of Highway 9 and Highway 23 in Harriston in the west, to Highway 400 just east of Cookstown in the east. The principal urban centres along the highway include Alliston, Shelburne and Mount Forest. Outside these towns, the highway travels through rural farmland across a large part of southwestern Ontario.