There was a combined approximately $84 million of farms and rural land for sale in Sangamon County, Illinois, recently on Land.com. The total size of all Sangamon County land and rural real estate for sale was 2,000 acres. Sangamon County ranks 14th in Illinois for the total acreage of land currently advertised for sale. Springfield had the most land for sale. From an economic perspective, government and state-level services contribute most to Sangamon County's overall GDP. Sangamon County is one of the ten biggest counties in Illinois (877 square miles). It's located in the Central Illinois region of the state.