There was a combined approximately $238 million of farmsand rural real estate for sale in Michigan's Allegan County recently on Land.com. The total of all Allegan County farms and rural real estate for sale was almost 100,000 acres. Allegan County ranks ninth in the state based on the combined acreage of land for sale of all the counties in the Wolverine State. Allegan had the most land for sale. From an economic perspective, manufacturing and related services are the main sectors in Allegan County. Allegan County is Michigan's 14th biggest county (1,833 square miles). It's located in the Southwest Michigan region of Michigan.