Treungen and Tveitsund were previously separate villages, but they have grown together and now form one large urban area.

The local hotel is a building that is characteristic of Treungen's early days as a travel interchange between road and railway.

The Telemarksveien (Norwegian National Road 41) passes through the village northwards towards Vrådal and southwards towards Åmli in Agder county.

Treungen has a warm-summer humid continental climate (Köppen: Dfb),[7] with cold winters and mild summers.

Various nearby mountain peaks offer hiking trails, including Hægefjell, Skornetten, and Skuggenatten.

Its peak at 706 metres (2,316 ft) above sea-level has panoramic views of surrounding areas including the village and adjacent lake Nisser.

[13] The trailhead for Skornetten, the highest point in Kyrkjebygdheia at 883 metres (2,897 ft) above sea-level, is situated by the seter at Espeli on the eastern side of Holmevatn and Breilivatn.

From the peak are views of Fyresdal, Vrådal, Kviteseid, Seljord, Hesthomvarden, Hjasufsknatten, and as far as Risør and the ocean outside Kragerø.

[17] The trail to the peak at Reinvassnuten lies by Reinsvatn Lake where the oldest cabin at Gautefall can be found (Reinsvasshytta).