A slow start to the 2014 housing market in Mercer County. There were four closed sales in January with a median price of $47,000. Those numbers from the Illinois Association of REALTORS. For the same period a year ago, six homes were sold in Mercer County with an average price of $83,000. Currently, there are 82-homes on the market in Mercer County. On average, a home sits on the market for 137 days until a closed sale.