Burgruine Poppberg, Medieval castle ruin in Birgland, Germany.

Burgruine Poppberg occupies a rocky plateau about 75 by 45 metres on the 652.6-metre Poppberg in the Franconian Alb, roughly 600 metres west-northwest of the village church. Its well-preserved palas, a rectangular building about 25 metres long and 12 metres wide, still stands three storeys high in rough rubble masonry, with dressed bossed stones at its southeast corner. A ring wall encloses the main castle and an outer courtyard, and a small square tower stood on the highest rock at the southwest.

The castle was probably built in the 13th century by the Counts of Sulzbach. It is documented between 1353 and 1373 as the property of Emperor Charles IV, passed to Margrave Otto of Brandenburg, and in 1379 to the Bavarian dukes Johann and Stephan, who sold it in 1395 to Count Palatine Rupert III. In 1505 it was incorporated into the Duchy of Sulzbach, and in 1550 the land was sold to farmers; the ruin passed to the Bavarian state in 1791 and is privately owned today.

The name Poppberg comes from the village below the summit, and the ruin is a listed Bodendenkmal (D-3-6535-0079) and Baudenkmal (D-3-71-116-23). Visitors can still trace the gate on the south side and the ring wall around the outer courtyard, whose unprotected remains are threatened by decay.

The castle ruins are freely accessible to visitors year-round without official facilities on-site, though the surrounding natural environment offers opportunities for hiking and outdoor activities with amenities available in nearby towns.

The tower stump on the highest rock was capped with brickwork in the 20th century; during World War II a "Flugwache" manned by anti-aircraft soldiers watched from here, reporting every aircraft to the control centre in Nuremberg. The same observation is said to have taken place during the pre-war Reichsparteitage.