Burg Ummendorf, Medieval castle in Ummendorf, Germany.

Burg Ummendorf is a castle in the village of Ummendorf in the Magdeburger Börde, Saxony-Anhalt. Its irregular three-winged layout in Renaissance style was built between 1535 and 1581 under the von Meyendorff family. The Romanesque bergfried, over 20 metres high, dates from the second half of the 12th century; its octagonal tower room was added in the 16th century. A Romanesque granary stands on the west side.

Archbishop Friedrich I of Wettin had a castle built here in 1178 to guard the border with what is now Lower Saxony. In 1389 Archbishop Albert of Magdeburg bought the castle and much of the village. From 1535 to 1581 the von Meyendorff family rebuilt it as a three-winged Renaissance complex, and in 1430 Magdeburg troops stormed it after raids by robber knights.

The Börde Museum, run by the Börde district, occupies part of the castle and shows agricultural machinery alongside a herb garden with more than 400 kinds of herbs and plants. The south wing houses an elementary school, so the site is still used daily by the village.

The site is easily accessible and hosts both museum spaces and an elementary school that share the facilities. Visitors should keep in mind that some areas may have restricted access during school hours.

The 380-volume library of 17th- and 18th-century books, including Bibles, church printed works, inventory books, invoices and population lists, was moved from the Oschersleben local museum to the Municipal Museum in Halberstadt in the 1960s and is to be housed in the Börde Museum in future.