Sylvia is a city in Reno County, Kansas, United States. As of the 2010 census, the city population was 218.
Sylvia is located at 37°57′28″N 98°24′32″W / 37.95778°N 98.40889°W / 37.95778; -98.40889 (37.957673, -98.408878). According to the United States Census Bureau, the city has a total area of 0.3 square miles (0.8 km²), all of it land.
As of the census of 2000, there were 297 people, 122 households, and 84 families residing in the city. The population density was 1,034.5 people per square mile (395.4/km²). There were 142 housing units at an average density of 494.6 per square mile (189.1/km²). The racial makeup of the city was 96.97% White, 0.34% Native American, 1.01% Asian, 0.67% from other races, and 1.01% from two or more races. Hispanic or Latino of any race were 1.68% of the population.