Tenna had an area, as of 2006, of 11.3 km² (4.4 sq mi).
 Of this area, 45.1% is used for agricultural purposes, while 34% is forested.
 Of the rest of the land, 1.1% is settled (buildings or roads) and the remainder (19.8%) is non-productive (rivers, glaciers or mountains).

The former municipality is located in the Safien sub-district of the Surselva district.
 It is a German-speaking collection of small settlements on a terrace above the west side of the Safien valley.
 It consists of the village of Tenna which is made up of the sections of Ausserberg, Mitte and Innerberg as well as the hamlets of Acla and Egschi along the valley road.
Tenna had an area, as of 2006, of 11.3 km² (4.4 sq mi).  Of this area, 45.1% is used for agricultural purposes, while 34% is forested.  Of the rest of the land, 1.1% is settled (buildings or roads) and the remainder (19.8%) is non-productive (rivers, glaciers or mountains).
The former municipality is located in the Safien sub-district of the Surselva district.  It is a German-speaking collection of small settlements on a terrace above the west side of the Safien valley.  It consists of the village of Tenna which is made up of the sections of Ausserberg, Mitte and Innerberg as well as the hamlets of Acla and Egschi along the valley road.
Tenna, Switzerland