Arma is a city in Crawford County, Kansas, United States. According to the 2010 census, the city's population was 1,481.
Arma was founded in 1894. It was named for W.F. Armacost, an original landowner.
A post office was opened at Arma in 1891, and remained in operation until it was discontinued in 1906.
Arma was a station on the Missouri Pacific Railroad.
Arma is located at 37°32′37″N 94°42′2″W (37.543679, −94.700472). According to the United States Census Bureau, the city has a total area of 1.14 square miles (2.95 km2), of which, 1.12 square miles (2.90 km2) is land and 0.02 square miles (0.05 km2) is water. It is located about 6 minutes' drive north of Frontenac, and about 8 minutes' drive east of Girard.
As of the census of 2010, there were 1,481 people, 657 households, and 372 families residing in the city. The population density was 1,322.3 inhabitants per square mile (510.5/km2). There were 736 housing units at an average density of 657.1 per square mile (253.7/km2). The racial makeup of the city was 97.0% White, 0.1% African American, 1.4% Native American, 0.1% Asian, 0.5% from other races, and 1.0% from two or more races. Hispanic or Latino of any race were 2.7% of the population.