Charlottensee, Natural monument and lake in Sparwiesen, Uhingen, Germany.

Charlottensee is a 0.9-hectare reservoir pond in Uhingen, dammed behind an earth embankment in the west and northwest that carries a farm track. From the dam it runs nearly 150 metres east-southeast, narrowing to a maximum width of 80 metres, and is largely ringed by reeds. A monk outlet near the dam drains it into the Tobelbach.

The lake was created in the early 15th century, possibly for fish farming for a monastery or as a cattle watering place. It was first mentioned by name in 1550, when it was the largest of five ponds; the other four were later filled in. In 1999/2000 it was dredged with a boat to counter silting, and the water-lily growth is now mown regularly.

The lake's name goes back to Charlottenhof, the estate just southwest of the water. Swans swim on it and are fed by visitors, herons nest at the shore, and migratory birds stop over. Yellow water lilies grow in the pond, and the reeds are mown and cleared each year.

A farm track runs over the dam on the west and northwest sides, giving the main access to the shore; the water lies east-southeast of it. The lake is bordered by the Birkenhau wood to the northeast and east, and by the Charlottenhof to the southwest. The outflow passes a monk near the dam into the Tobelbach, which reaches the Fils after about 1.2 km.

The lake anchors several longer walking routes in the area, including the Schnapsbuckeltour and the Sauerbrunnen circular walk. These paths link nearby villages and reveal changing landscapes across the wider region.