Events from the year 1851 in Denmark.

• Monarch – Frederick VII^[1]
• Prime minister – Adam Wilhelm Moltke

• February – Danish troops return to Copenhagen from the First Schleswig War.
• 1 May – Natalie Zahle launches a programme for the training of female private teachers, an initiative which will eventually develop into N. Zahle's School.
• 16 October – The first section of the Lübeck–Lüneburg railway is opened.

• Hagen & Sievertsen is founded in Odense.

• 31 March – The Charlottenborg Spring Exhibition opens.
  • Wilhelm Marstrand's painting of Church-Goers Arriving by Boat at the Parish Church of Leksand on Siljan Lake is part of the exhibition.^[2]

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  Wilhelm Marstrand: Church-Goers Arriving by Boat at the Parish Church of Leksand on Siljan Lake, Danish National Gallery.

• 3 January – Viggo Johansen, painter (died 1935)
• 5 January – Johanne Bindesbøll, textile artist (died 1934)
• 26 February – Peter Kristian Prytz, physicist (died 1929)
• 10 March – Heinrich Wenck, architect (died 1936)

• 24 April – Harald Giersing, painter (died 1927)

• 16 August – Harald Jerichau, painter (died 1878)

• 21 November – Carl Locher, painter (died 1915)

• 23 July – Peder Severin Krøyer, painter (died 1909)

• 12 November – Karl Jensen, painter (died 1933)

• 9 March – Hans Christian Ørsted, physicist and chemist, discoverer of electromagnetism (born 1777)
• 11 July – Ole Jørgen Rawert, government official and topographic painter (born 1786)
• 25 August – Johan Christian Drewsen, businessman and agronomist (born 1777)
• 20 December – Gebhard Moltke, nobleman, landowner and civil servant (born 1764).^[3]