Geldern is a city in the federal German state of North Rhine-Westphalia. It is part of the district of Kleve, which is part of the Düsseldorf administrative region. The Dutch province of Gelderland is named after this city.

Gelderland, also known as Guelders in English, is a province of the Netherlands, occupying the centre-east of the country. With a total area of 5,136 km2 (1,983 sq mi) of which 176 km2 (68 sq mi) is water, it is the largest province of the Netherlands by land area, and second by total area. Gelderland shares borders with six other provinces and the German state of North Rhine-Westphalia.