Trettestølane and Nystølane belongs together as one mountain farm, and has done so as long as people can remember. The first summer farm was probably built around the 16th Century and they assume that Trettestølane is the oldest of the farms.
Around the beginning of 1900 you could find 18 farms here, and in 1990 there was a total of 14 farms as 4 farms had merged or had closed down. In 2010 there were still 12 active summer farms here, and this area is therefore one of the most active summer pastures in the municipality. The Nystøl Church was built in 1896 and belongs to the summer farms.
Trettestølane is located as far in on Votndals-/ Liagardsåsen as you can drive. You can drive via Liagardane or Votndalen by Sehl. You can park by the lavvo.