Arlington is a city in Reno County, Kansas, United States. As of the 2020 census, the population of the city was 435. Arlington was founded in …Arlington is a city in Reno County, Kansas, United States. As of the 2020 census, the population of the city was 435. Arlington was founded in 1877. It was named after Arlington, Massachusetts. The first post office in Arlington was established in February 1878.