Both are in the municipalities of Bischoffen and Hohenahr in the county of Lahn-Dill-Kreis and about 15 km northwest of the town of Gießen in Hesse.

On the lakeshores lie the villages of Ahrdt and Mudersbach, both part of the parish of Hohenahr.

Since 1991 the dam has impounded the River Aar, a left-hand tributary of the Dill in the Gladenbach Uplands.

Other uses are: raising low water levels, electricity generation, fishing and recreation.

Its operator is the county council of Lahn-Dill-Kreis and the Dillgebeit Water Association.