Philip II of Hesse-Rheinfels (1541, Marburg – 1583), also called Philip the Younger, was the first Landgrave of Hesse-Rheinfels. Philip was the third son of Landgrave Philip the Magnanimous and Christine of Saxony (1505–1549). After his father's death in 1567, the Landgraviate of Hesse was divided between the four sons out of the late landgrave's first marriage. Philip the Younger received the portion around the Rheinfels Castle and city of St. Goar on the left bank of the Rhine. The county consisted mainly of the former Lower County of Katzenelnbogen with its four Ämter Rheinfels (with the city of St. Goar and the residence Rheinfels Castle) on the left bank of the Rhine, and Braubach, Reichenberg and Hohenstein on the right bank.