Ralph Jacobs Airport (ICAO: 27LL) is a small, privately owned general aviation airfield located near Valmeyer, Illinois, in Monroe County. It serves local private pilots and light aircraft operations in the southwestern Illinois region, not far from the Mississippi River. The airport does not offer scheduled commercial airline service and has no IATA code, reflecting its status as a private general aviation facility. It is one of many small airstrips that support personal and recreational flying in rural Illinois.