Effingham is a city in Atchison County, Kansas, United States. The population was 588 at the 2000 census. Effingham was named in honor of Effingham H. Nichols, an early promoter of the Central Branch Union Pacific Railroad.
Effingham is located at 39°31′22″N 95°23′55″W / 39.52278°N 95.39861°W / 39.52278; -95.39861 (39.522774, -95.398633).
According to the United States Census Bureau, the city has a total area of 0.5 square miles (1.4 km²), all of it land.