Segeberg is a district in Schleswig-Holstein, Germany. It is bounded by (from the southwest and clockwise) the districts of Pinneberg, Steinburg and Rendsburg-Eckernförde, the city of Neumünster, the districts of Plön, Ostholstein and Stormarn, and the city state of Hamburg. Since then the district has considerable grown twice: In 1932 parts of the dissolved district of Bordesholm joined the district; and in 1970 the city of Norderstedt became part of the district.