The Schlei (Dens: Slien) is a narrae inlet o the Easter Seas in Schleswig-Holstein in northren Germany. It stretches for approximately 20 mile frae the Easter near Kappeln an Arnis tae the ceety o Schleswig. Alang the Schlei are mony smaw bays an swamps. It separates the Angeln peninsula tae the north frae the Schwansen peninsula tae the sooth.

Schlei near Kappeln
Cairt showin the Schlei

The important Viking dounset o Hedeby wis locatit at the heid o the firth (fjord), but wis later abandoned in favor o the ceety o Schleswig. A museum haes been biggit on the steid, tellin the story o the abandoned toun.

Coordinates: 54°35′N 9°50′E / 54.59°N 9.83°E / 54.59; 9.83