Weißenfels was a district (Kreis) in the south of Saxony-Anhalt, Germany.

Near the small town of Goseck, archaeologists, discovered in 1999 was the oldest solar observatory in Europe, beating Stonehenge by more than 2,000 years.

Around 5,000 BC, the circular trench with a diameter of 75 meters was surrounded with wood palisades, with three openings which allowed to measure the date of the spring and autumn equinox.

Excavations on the site are planned to continue until 2007.The district in today's borders was created in 1994 when the two previous districts Weissenfels and Hohenmölsen were merged.

In the east of the district is the lignite open pit mining area of Hohenmölsen.