Uetersen is a town in the district of Pinneberg, in Schleswig-Holstein, Germany. It is situated approximately 7 km (4.3 mi) south of Elmshorn, and 30 km (19 mi) northwest of Hamburg at the small Pinnau River, close to the Elbe river. Uetersen is home to the Rosarium Uetersen, the oldest and largest rose garden in Northern Germany, created in 1929.

Schleswig-Holstein is the northernmost of the 16 states of Germany, comprising most of the historical Duchy of Holstein and the southern part of the former Duchy of Schleswig. Its capital city is Kiel; other notable cities are Lübeck and Flensburg. It covers an area of 15,763 km2 (6,086 sq mi), making it the 5th smallest German federal state by area.