Runkel is a town on the Lahn River in Limburg-Weilburg district in Hesse, Germany.

Runkel lies in the Lahn Valley on both sides of the river between the Westerwald and the Taunus, some eight kilometres east of Limburg.

Runkel borders in the north on the community of Beselich and the town of Weilburg, in the east on the communities of Weinbach and Villmar and in the south and west on the town of Limburg.