|Geographical location||District of Leipzig|
|Places on the shore||Borna|
|Altitude above sea level|
|Maximum depth||13 m|
The Harthsee is like the neighboring Bockwitz See a Tagebaurestsee consisting of the brown coal mining has emerged Borna-Ost. It is located in the Leipziger Neuseenland east of Borna and north of Frohburg and was flooded from 1987 to 1995. It is a certified EU bathing water .
The Harthsee is located in the Leipzig district between Borna in the north-west and Frohburg in the south. The Borna district of Neukirchen borders the lake in the west and the Frohburg districts of Nenkersdorf in the east and Bubendorf in the south. The A 72 passes to the west and south, the Borna-Süd exit is just under 4 km north of the lake.
With the closure of the Borna-Ost opencast mine in 1985, the "Restloch Nenkersdorf" in the southern part of the opencast mine was flooded from swamp water from the Bockwitz opencast mine opened in 1982, water from the Harthbach and rising groundwater. After the Bockwitz opencast mine was closed in 1992, the discharge of swamp water ended a year later. After that, the rise in the water level was only caused by groundwater and surface water. The 87 hectare lake reached its final level in 1995.
The Harthsee is being expanded for local recreation. The Harthsee-Verein tries to make the water part of the emerging lake network in the southern Leipzig area. A campsite is planned. The lake is used as a bathing and fishing water. Parking spaces have been created on both the Nenkersdorf and Neukirchen beaches.