Rosalia is an unincorporated community and census-designated place (CDP) in Butler County, Kansas, United States. As of the 2020 census, the population was 149. It is located approximately east of El Dorado.
Rosalia was platted in 1883. The town was named by its first postmaster for his wife.
In 2014 and 2018, the Symphony In The Flint Hills, an outdoor symphony music event, was held a few miles northeast of Rosalia. In 2014, the attendance was over 7000 people.
Rosalia is located at (37.8152985, -96.6197416), in the scenic Flint Hills, roughly east of El Dorado.
The climate in this area is characterized by hot, humid summers and generally mild to cool winters. According to the Köppen Climate Classification system, Rosalia has a humid subtropical climate, abbreviated "Cfa" on climate maps.
Rosalia has a post office with ZIP code 67132. The post office was established in 1870.
The community is served by Flinthills USD 492 public school district. The Flinthills High School mascot is the Mustangs.