1645 in Denmark
Events from the year 1645 in Denmark. Incumbents 

 Monarch — Christian IV
 Steward of the Realm — Corfitz Ulfeldt

Events 
 3 March — Simon Paulli gives his first public lecture in the new Domus Anatomica in Copenhagen. 25 May   sinks near Buskär outside the harbour of Gothenburg. 13 August — The Second Treaty of Brömsebro is signed, putting an end to the Torstenson War. The island Øsel is ceded to Sweden. Undated
 Stephanius publishes Saxonis Grammatici Historiæ Danicæ Libri XVI, a Latin edition of Saxo Grammaticus's Gesta Danorum. Culture

Art
 Abraham Wuchters creates a full-length portrait of Ulrik Christian Gyldenløve. Births

Deaths 
 January 31 — Hans Ulrik Gyldenløve, diplomat, illegitimate son of Christian IV

References 

 
Denmark
Years of the 17th century in Denmark