This layout has existed at Keldur since the middle ages. In addition to the farmhouse buildings and the church, other structures include storehouses, a smithy, a millhouse, a cattleshed, a stable, a sheep corral, a tunnel, etc. Like other turf buildings, these have often been rebuilt. They were built in their present form following major earthquakes in 1896 and 1912. The farmstead is built from lava rock from nearby Mt. Hekla, which is in plentiful supply around the farm, together with driftwood from Landeyjarsandur, where Keldur owned rights to that resource. Driftwood was an important source of timber for construction.Since the mid-20th century the farmhouse has been a part of The National Museum Building Collection, and has been maintained as such.
Keldur is well known in Icelandic history. According to the Njálssaga, it was the home of Ingjaldur Höskuldsson. In the 12-13th century Keldur was an important manor owned by the powerful Oddi clan, and their chieftain, Jón Loftsson (d. 1197) lived there at the end of his life.
Sand drift has long been a problem in this area, and efforts to combat the encroachment were at their height in the late 19th century. Protective barriers were built, which can still be seen today. On the Keldur estate are remains of 16-18 farmsteads, including Sandgil and Tröllaskógur which play a part in the Njálssaga.
Guðmundur Brynjólfsson (1794–1883), who farmed at Keldur for fifty years, made extensive improvements to the buildings. In his time three new structures were added to the east of the pantry. Skúli Guðmundsson (1862–1946), one of Guðmundur's 25 children, was the last person to live in the old farmhouse. He understood the historical importance of the buildings, and collected a large amount of information about them. In 1942 the old farmhouse was purchased by the National Museum of Iceland, while Skúli continued to live there until his death in 1946. After Skúli's time, various objects which had been preserved at Keldur were also purchased by the Museum.
The farmhouse is now part of the National Museum Historic Buildings Collection.