District of Duchy of Lauenburg

The flag of the modern district of the Duchy of Lauenburg shows the district's coat of arms on a white field between two black horizontal bands. The silver horse head on a red shield was the historical coat of arms of the Duchy. When the Duchy was formally integrated into the Kingdom of Prussia in 1865, a black and white border and a crown were added to the coat of arms to symbolise the Kingdom of Prussia.