Dow, IllinoisDow is an unincorporated community in Jersey County, Illinois, United States.HistoryDow was laid out in 1883 when the railroad was extended to that point. The community derives its name from its founder, John McDow.EducationDow was served by the public K-12 Jersey Community Unit School District 100. District schools in Dow included the Dow Elementary School. The school was closed in June 2011 due to district realignment.