You are looking over a meandering river, Svínadalsá, that originates in the mountain farthest from you, straight to the right. Svínadalsá empties into one of Iceland's most famous salmon river Laxá í Kjós, which is the main river in this area, Kjós.
If you look over the river, take note of two grey houses that you see in the distance, close to a mountain, that belong to a farm that's located there; Írafell. One of the most famous ghosts in Iceland, Írafells-Móri, resided there for a long time in the 19th century, following around members of that family.
If you look to the left you can see two yellow buildings in the hills beneath Sandfell mountain. This is Vindáshlíð, YMCA summer camps for girls.
The cache is a traditional plastic container and contains a logbook and five items. Feel free to exchange them for something else :)