Aschaffenburg is a town in northwest Bavaria, Germany. The town of Aschaffenburg is not considered part of the district of Aschaffenburg, but is the administrative seat.

Aschaffenburg belonged to the Archbishopric of Mainz for more than 800 years. The town is located at the westernmost border of Lower Franconia and separated from the central and eastern part of the Regierungsbezirk (administrative region) by the Spessart hills, whereas it opens towards the Rhine-Main plain in the west and north-west. Therefore, the inhabitants speak neither Bavarian nor East Franconian but rather a local version of Rhine Franconian.

The town is located on both sides of the Main in the southwest part of Germany, 41 kilometers (25 mi) southeast of Frankfurt am Main. In the western part of the municipal territory, the smaller Aschaff flows into the Main. The region is also known as Bayerischer Untermain ("Bavarian Lower Main"). Aschaffenburg lies in the far northwest of the state of Bavaria, close to the border to the state of Hesse.

The main sights of Aschaffenburg are the Schloss Johannisburg, built 1605-1614 by Archbishop Johann Schweikhard von Kronberg, which contains a library with a number of incunabula, a collection of engravings and paintings; the Pompejanum, a replica of a Roman town house discovered in Pompeii commissioned by King Ludwig I. and opened in 1850; the St. Peter und Alexander collegiate church, founded in the second half of the 10th century, but dating in the main from the early 12th century on, in which are preserved various monuments by the Vischers, a sarcophagus with the relics of Saint Margaret, and a painting by Matthias Grünewald; the Capuchin hospital; a theatre, which was formerly a house of the Teutonic Order; several mansions of the nobility; and the historical old town. Across the river are the Park and Schloss Schönbusch.

The graves of Clemens Brentano and his brother Christian Brentano (died 1851) and that of Wilhelm Heinse can be found in the Altstadtfriedhof (Old Town Cemetery).