The Seeweiher is a reservoir north of the village of Waldernbach in the municipality of Mengerskirchen (county of Limburg-Weilburg) in the Westerwald in the German state of Hesse. It impounds the Vöhlerbach, a tributary of the Kallenbach which, in turn, flows into the River Lahn. It has a surface area of 13 hectares.

The Seeweiher was impounded in 1452 and is thus one of the oldest reservoirs in Hesse.

There was a campsite on the shores of the bathing lake and, since 1978, there has been a weekend village with 66 houses. Once a year the Westerwald Water Working Group holds a water work assessment for Newfoundland and Landseer dogs on land owned by the DLRG by the Seeweiher.

• Hessian State Officwe for the Environment and Geology: Seeweiher Mengerskirchen. In: Badeseen in Hessen, retrieved 13 May 2009
• Information on the Seeweiher
• Information on the Westerwald Water Working Group