Main) is a municipality in the Aschaffenburg district in the Regierungsbezirk of Lower Franconia (Unterfranken) in Bavaria, Germany.

In the 20th century, the town was the site of the, now decommissioned, Großwelzheim Nuclear Power Plant.

The Pragmatic Army overcame the French, thus giving rise to the legend of the "Wandering Englishman", which has been handed down in Dettingen to this day.

The name Karlstein supposedly, according to a traditional anecdote, goes back to Charlemagne (who is called Karl der Große in German).

It comes from Late Gothic times and is found in Saint Hippolytus's Church (Kirche St. Hippolyt) in the constituent community of Dettingen.

Within community limits, Germany's first nuclear power station was built, although it was only experimental.

On 13 November 1960, the Kahl Nuclear Power Plant, which despite the name is wholly within Karlstein's limits, came into service.

[clarification needed] On 25 November 1985, after running for 25 years, the power station was shut down.