Nachusa, IllinoisNachusa is an unincorporated community in Lee County, Illinois, United States, located east of Dixon. Nachusa has a post office with ZIP code 61057. Nachusa is located on the old C&NW main line between Chicago and Omaha.HistoryA post office called Nachusa has been in operation since 1855. The name Nachusa is said to be derived from Sac or Fox Indian.DemographicsNachusa first appeared as a census designated place in the 2020 U.S. census.EducationIt is in the Dixon Unit School District 170. The comprehensive high school of that district is Dixon High School.