At Jökulsárlón (top right in the map above) we turned around and headed back west, across the Breidamerkursandur glacial outwash plain. For a long time, we could see this glacier in the distance:
...but it was only when we got close that we noticed a gravel road leading in toward it. A drizzly rain was starting to fall, and clouds were rolling in, but we decided to see if we could get a better view. The road led all the way in to a hill overlooking the glacial tongue, and when we got out and approached the crest of the hill on foot, this sight greeted us:
Another glacial lagoon! But this time, we were a lot closer to the glacier itself, and could not only see the glacier much better, but also its relationship to the lake and to the icebergs, and the terminal and lateral moraines. Apart from three or four hikers and a couple of photographers, we were alone. As the map shows, there is a walking path (indicated in red) that goes from this lagoon all the way over to Jökulsárlón. That would have been a long hike even if it were morning instead of late afternoon, and not raining, so we noted it as a possibility for another time.
The pictures here can't adequately convey the size of this place or the height and massiveness of the glacier itself; I felt awed to be this close to it. The crevasses you can see in this picture are far deeper than the height of a person, and the iceberg at left is the size of a multi-storey house.
When the steady drizzle turned to real rain, and the light became flat, we hiked back to our car and headed for our night's lodging in the little settlement of Hof, still a good drive to the west.