Athelstan is a tiny hamlet in Taylor County, Iowa, United States, along the Platte River, on the border with Missouri; it is majority owned by the Young family.

Athelstan got its start following construction of the Chicago Great Western Railroad through the territory.

[6] In 2004, after years of rural flight, the depopulated town was disincorporated, ending its existence as a self-governing community.

A small amount of its platted southern portions encroached into Missouri.

According to the 2010 census, the CDP has a total area of 0.13 square miles (0.34 km2), all land.

There were no families and 31.6% of the population living below the poverty line, including no under eighteens and 50.0% of those over 64.