Mapleton is a city in Bourbon County, Kansas, United States. As of the 2020 census, the population of the city was 96. Mapleton was origina…Mapleton is a city in Bourbon County, Kansas, United States. As of the 2020 census, the population of the city was 96. Mapleton was originally called Eldora, and under the latter name was founded in 1857. A post office was established under the name Mapleton in 1857. The first store in Mapleton opened in 1858. In 1861, the name of the town was officially changed to Mapleton, matching the name of the post office. Mapleton was so named for a grove of maple trees near the original town site.