It is situated approximately 8 km northeast of Elmshorn, and 30 km northwest of Hamburg.
The Hamburg-Altona–Kiel railway should go through Barmstedt but as Elmshorn had more habitans the line went through it.
Lutzhorn is located about 4 km north of Barmstedt.
It is twinned with Barmstedt, Germany, and Dodgeville, Wisconsin, U.S.A..