1878 in Denmark

Events from the year 1878 in Denmark.

• Monarch – Christian IX^[1]
• Prime minister – J. B. S. Estrup

• 3–9 July – The 11th Scandinavian Scientist Conference is held in Copenhagen.
• 9 May – The panserbatteri Helgoland is launched.
• 21 December – Princess Thyra of Denmark is wed to Ernest Augustus, Crown Prince of Hanover in Copenhagen. The couple continue to Fredensborg Palace after the wedding ceremony.

• 25 September – The opera Drot og marsk is first performed at the Rotal Danish Theatre in Copenhagen.

• 1 January – Agner Krarup Erlang, mathematician, statistician and engineer
• 6 January – Adeline Genée, Danish-British ballet dancer (died 1970)
• 10 February – Johannes Berggreen, businessman (died 1963)
• 13 March – Lau Lauritzen Sr., film director, screenwriter and actor (died 1938)
• 11 April – Holger-Madsen, actor (died 1943)
• 17 March – Gudmund Nyeland Brandt, landscape architect (died 1945)

• 30 July – Jørgen Skafte Rasmussen, businessman, company founder (died 1964)
• 2 August – Princess Ingeborg of Denmark, duchess of Västergötland (died 1958 in Sweden)
• 25 September – Holger Thiele, astronomer (died 1946)

• 9 November – Povl Baumann, architect (died 1963)
• 24 December – Thomas Madsen-Mygdal, politician, former Danish prime minister (died 1943)

• 6 March – Harald Jerichau, painter (born 1851)
• 4 December – David B. Adler, businessman (born 1826)