Most of the large lakes of Upper Austria are situated in the south (Salzkammergut): Almsee, Attersee, die Gosauseen, Hallstätter See, Irrsee, Langbathseen, Mondsee, Offensee, Traunsee and Wolfgangsee. In the Oberinnviertler Seenplatte on the border with Salzburg, you can find small lakes which are very warm in summer: Holzöstersee, Höllerer See, and Ibmer See.