Willoughby Farms Estates in Algonquin Willoughby Farms Estates is a single family home neighborhood in Algonquin, Illinois. Activity in Willoughby Farms Estates for the past 6 months Homes Sold Lowest Price Highest Price Average Price 3 $268,000 $360,000 $316,000 3 homes sold in Willoughby Farms ... 03/01/2012