It has been largely rebuilt since an 1836 fire, and possesses a castle with various collections, a museum of antiquities, an old town hall and churches.

The nearby ridge of rocks called the Teufelsmauer ('Devil's Wall') offers views across the plain and into the deep gorges of the Harz.

In 1180–82 Frederick Barbarossa had Blankenburg devastated because it had pledged "sole allegiance" to the Welf, Henry the Lion.

Following the death of the last count of Regenstein, John Ernest, the county went in 1599 as an agreed enfeoffment (erledigtes Lehen) back to the dukes of Brunswick-Lüneburg.

At the same time the County of Blankenburg was elevated to the status of an imperial principality (Reichsfürstentum) which was ruled independently until 1731, but then, because Louis Rudolf became a duke, was reunited with Brunswick where it remained.

Louis XVIII also stayed in Blankenburg under the name of Count of Lille from 24 August 1796 to 10 February 1798, after his escape from Dillingen.

In a notorious campaign by Brunswick SS commander, Jeckeln, in September 1933, 140 communists and social democrats were herded together in the inn, Zur Erholung.

The tunnels of the Regenstein-Blankenburg facility were used from 1974 by the National People's Army (NVA) in the GDR as a large ammunition depot.

[5] On 1 January 2010 the town Blankenburg absorbed the former municipalities Cattenstedt, Derenburg, Heimburg, Hüttenrode, Timmenrode and Wienrode.

The most important economic factors for Blankenburg (Harz) are tourism and facilities for spa and health industry.

The largest industrial concern in the town is the Harzer Werke Motorentechnik with about 60 employees, which grew out of a grey iron foundry founded in about 1870.