Harrisville is a city in the U.S. state of Michigan and the county seat of Alcona County. It is located on Lake Huron, in the northern part of Michigan's Lower Peninsula. The city is surrounded by Harrisville Township but is administratively autonomous from it.
At the 2020 census, Harrisville had a population of 437, making it the sixth-smallest city by population in Michigan. Its position on Lake Huron gives it a role in regional maritime activity, and it is designated an official Michigan Department of Natural Resources Harbor of Refuge.