Nachusa is an unincorporated community in Lee County, Illinois, United States, located east of Dixon. As of the 2020 census, Nachusa had a population of 137. Nachusa has a post office with ZIP code 61057. Nachusa is located on the old C&NW main line between Chicago and Omaha.
A post office called Nachusa has been in operation since 1855. The name Nachusa is said to be derived from Sac or Fox Indian.
Nachusa first appeared as a census designated place in the 2020 U.S. census.
It is in the Dixon Unit School District 170. The comprehensive high school of that district is Dixon High School.