From 1061 to 1070 Count Otto II held the stem duchy of Bavaria as an Imperial fief, but lost it again because of his involvement in the Saxon plot against King Henry IV.

A part of Northeim was devastated by a fire in 1832 when the representative town hall dating from the Middle Ages and more than 40 houses burnt down.

Northeim, under the pseudonym of Thalburg, is the subject of William Sheridan Allen's book The Nazi Seizure of Power (ISBN 0-531-05633-3), a comprehensive study of the success of Nazism at town level.

However, even its critics say that the book is crucial to our understanding of Nazi Germany and has played a key role in shaping scholarship.

[4] Imbshausen, the site of a post-World War II British sector Displaced Persons camp, was incorporated into the town in 1974.

The town is also home to a puppet theatre, Theater der Nacht, which since 2001 has been housed in a redesigned fire station.

Northeim also provides a small grass airfield (ICAO locator code: EDVN) due east of the town.

The oldest church of Northeim is Saint Fabian's and Sebastian's Chapel which was built in a typical gothic style in the middle of the 14th century and renovated in 1985/86.

Theater der Nacht is located in an old firestation, rebuilt and designed by the artists Ruth und Heiko Brochhausen.