Geldern lies in the plains of the lower, northern Rhineland, west of the Rhine. Its average elevation is 27 m AMSL. The river Niers, a tributary of the Meuse (Maas), flows through Geldern. The stream Gelderner Fleuth flows into the Niers in Geldern.
Geldern is subdivided into the following boroughs:
The first coat of arms of the city of Geldern was a shield with three medlars, referring to an event in the dragon legend. The lion of Guelders, recognizable in the present coat of arms, has been used since the Middle Ages.
According to folk legend, local noblemen Wichard and Lupold of Pont fought a fire-breathing dragon around 878. They found it under a medlar tree, and one of them stabbed it with his spear. The dying dragon rattled two or three times: Gelre! Gelre!. In commemoration of this heroic feat, the Lords of Pont founded the city of Geldern at the confluence of the Niers and the Fleuth.
The city of Geldern was first documented in 812. Several versions of the name have been used: Gelre, Gielra, Gellero, Gelera and similar. The probable ancestor of the Counts of Guelders was Gerhard Flamens, who received Wassenberg as a fief from Emperor Henry II in 1020. His great-grandson Gerhard IV of Wassenberg was the first to call himself Count of Guelders (as Gerhard I), from 1096. The title "count" came from other properties, probably in Teisterbant. From 1125 only the title of Guelders was used. Wassenberg itself was given to the Duke of Limburg (and later to Jülich) as a wedding gift in 1107. The counts of Guelders moved their residence to the castle in Geldern, that was built probably around this date at the crossing of the Niers. The castle and the accompanying medieval settlement were the origin of the present city, and also gave its name to the county and later duchy of Guelders.