Burg Jesberg, Medieval castle in Jesberg, Germany.

Burg Jesberg is the ruin of a Romanesque hill castle begun around 1200 on the 280 m Schloßberg above Jesberg, on the old Fritzlarer Straße trade road. Its Romanesque bergfried survives, along with parts of the palas, cellars and ring walls; the rest of the defences were rebuilt from 1425 to 1426 under Happel Katzmann and a wall ditch was dug.

Construction began in the late 1100s and continued into the early 1200s to create a stronghold for local rulers. In 1241 the fortress came under the control of Archbishop Siegfried III, linking it to ecclesiastical power in the region.

The name Jesberg derives from "Jagsperg" or "Jagesburg", the form used for the castle and court of "Lenswideshusen" after the von Linsingen sold it to Mainz in 1241. The castle stood on the old Fritzlarer Straße, one of Hesse's oldest trade roads linking the Wetterau with Fritzlar and Gudensberg. From April to October the tower is open daily from 9 to 20 and gives a view over Jesberg and the Kellerwald.

The climb to the castle is free and follows marked walking paths up the hillside from the town. Parking is available at the base, and the ascent involves a steady uphill walk with good footing throughout.

Stone from the ruins was taken and reused to build houses in town for many decades until a merchant bought the site in 1820 to stop the dismantling. Without his intervention, very little of what stands today would have survived.