Liebenburg is a municipality in the district of Goslar, in Lower Saxony, Germany.

The municipal area is situated north of the Harz mountain range, within the eastern Salzgitter Hills of the Innerste Uplands. It borders on the district capital Goslar, approx. 12 km (7.5 mi) in the south; the adjacent municipalities in the north are Salzgitter-Bad and Schladen in Wolfenbüttel District.

The municipality comprises Liebenburg proper (with 2,140 inhabitants) and the following nine villages, which were incorporated on 1 July 1972 with the following population as of 30 June 2018:

• Dörnten (1,189 inhabitants) with Kunigunde
• Groß Döhren (872)
• Heißum (301)
• Klein Döhren (420)
• Klein Mahner (333)
• Neuenkirchen (206)
• Ostharingen (246)
• Othfresen (1,902) with Heimerode and Posthof
• Upen (317)

Archaeological excavations of a gallery grave indicate a settlement of the area in the Late Neolithic. The former Saxon estates in 1235 belonged to the territory of the newly established Prince-Bishopric of Hildesheim.

From 1292 to 1302, Prince-bishop Siegfried II of Querfurt had the Levenborch spur castle erected in the Salzgitter Hills, near where his episcopal lands bordered on the Principality of Brunswick-Wolfenbüttel. From 1366 it was pawned by his successors to the citizens of Braunschweig, important to secure the trade route to the Imperial City of Goslar.

The castle was seized by the warlike duke Henry V of Brunswick-Wolfenbüttel after the Hildesheim Diocesan Feud in 1523 and temporarily served as hidden residence of his mistress Eva von Trott. The Catholic duke in turn lost it to the Protestant Schmalkaldic League, whose troops campaigned the Brunswick lands from 1542 until their final defeat in the 1547 Battle of Mühlberg. During the Thirty Years' War, the stronghold was used as headquarters by the Imperial Generalissimo Albrecht von Wallenstein in 1625, it was occupied by Swedish troops in 1633, and reconquered by the Imperial Army in 1641.

By a 1643 peace treaty with the Braunschweig dukes, the heavily damaged castle was restored to Hildesheim, while day laborers and craftsmen lived within its walls. The Hildesheim prince-bishops promoted the settlement of Catholic families. The castle itself was partly rebuilt in a Baroque style by the order of the Wittelsbach prince-bishop Clemens August until construction work was abandoned due to the outbreak of the Seven Years' War in 1756. After the bishopric was finally secularised in 1802, Liebenburg fell to the Kingdom of Hanover in 1814.

Year Inhabitants 1821 4464 1848 5710 1871 5737 1885 5727 1905 6535 1925 6375

Year Inhabitants 1933 6167 1939 8206 1946 13.208 1950 13.700 1956 12.279 1961 11.687

Year Inhabitants 1968 11.143 1970 10.982 1975 10.405 1980 9851 1985 9502 1990 9655

Year Inhabitants 1995 9803 2000 9693 2005 9431 2010 8777 2011 8620

(from 1968 on numbers of inhabitants as of 31 December)

Seats in the municipal assembly (Gemeinderat) as of 2011 local elections:

• SPD: 11 seats
• CDU: 8
• Greens: 1
• Die Linke: 1
• Free Voters: 1

Elections in September 2016:

• SPD: 10 seats
• CDU: 7 seats
• AfD: 2 seats
• Alliance 90/The Greens: 1 seat
• FDP: 1 seat
• The LEFT: 1 seat

• Since October 2013: Alf Hesse (SPD)
• 1996-2013: Hubert Spaniol (SPD)