Hrútárjökull is an outlet glacier of Öræfajökull which is at the SW edge of Vatnajökull. Öræfajökull denotes both the glacier and the stratovolcano that lies underneath it. Iceland's highest mountain (Hvannadalshnjúkur, 2110m) is situated on the crater rim of Öræfajökull.
Fjallsárlón is a glacial lagoon just west of better known Jökulsárlón. It is fed by yet another outlet glacier of Öræfajökull/ Vatnajökull, Fjallsjökull.

de.wikipedia.org/wiki/%C3%96r%C3%A6faj%C3%B6kull