Avon is a census-designated place in Powell County, Montana, United States. The population was 124 at the 2000 census. The town sits along the Little Blackfoot River, and serves as a gateway to the Beaverhead-Deerlodge National Forest.The post office was opened in 1884 by Bill Cramer. The town was named Avon after the Welsh word for river. The town served as a supply point for nearby ranchers, prospectors, and miners.The town includes the Fitzpatrick Ranch Historic District, a designated location on the National Register of Historic Places.Avon is located at 46°35′57″N 112°35′56″W / 46.59917°N 112.59889°W / 46.59917; -112.59889.According to the United States Census Bureau, the CDP has a total area of 13.4 square miles, all of it land.As of the census of 2000, there were 124 people, 48 households, and 28 families residing in the CDP. The population density was 9.3 people per square mile. There were 62 housing units at an average density of 4.6 per square mile.