Rogen (Southern Sami: Rovje) is a lake situated mainly in Härjedalen, Sweden with a small portion crossing the Norwegian border. It is the source of Sweden's longest river, Klarälven.
On the Swedish side of the border, Rogen Nature Reserve is centred on the lake. In Norway, Rogen lies inside Femundsmarka National Park in the municipality of Engerdal in Hedmark county and also in the municipality of Røros in Sør-Trøndelag county. The lakes Nedre Roasten and Femunden lie just to the west of Rogen.