The Kleiner Feldberg is the second-highest mountain in the Taunus mountain range, located in Hesse, Germany.

The Großer Feldberg is located in its immediate neighbourhood.

In 1913, a meteorological and geophysical observatory was built there by German meteorologist Franz Linke.

In 1988 an astronomical observatory was built on the mountain's top.

The source of the Weil River and a small castle of the Limes Germanicus are located at its northern base.