(as of Dec. 31st)[3] Nienburg, including quarters The major reason for the emergence and development of Nienburg into the largest city in the Middle Weser region was its location at a convenient ford in the Weser River, leading to multiple trade routes radiating from the location.

From 1582 until 1866 the Guelph (Welf) Dukes of Brunswick-Lüneburg controlled the county, except for Napoleonic French rule from 1803 to 1813.

During World War II, it was the location of German prisoner-of-war camps Oflag X-B and Stalag X-C, in which French, Polish, Belgian, Romanian, Serbian, Italian and Soviet POWs were held.

In the wake of the war, a large number of livestock was killed in the region by an unknown predator, called Lichtenmoor Strangler.

[5] The 38 members of the "Stadtrat" are divided among: The elections in September 2016 showed the following results: Nienburg is twinned with:[6]