The Landgraviate of Hesse-Kassel (), spelled Hesse-Cassel during its entire existence, was a state in the Holy Roman Empire that was directly subject to the Emperor. The state was created in 1567 when the Landgraviate of Hesse was divided upon the death of Philip I, Landgrave of Hesse. His eldest son William IV inherited the northern half of the Landgraviate and the capital of Kassel. The other sons received the Landgraviate of Hesse-Marburg, the Landgraviate of Hesse-Rheinfels and the Landgraviate of Hesse-Darmstadt.