Tretten is located in the Gudbrandsdal valley, along the Gudbrandsdalslågen river in the southern part of the municipality.

It is located along the European route E6 highway, about 25 kilometres (16 mi) north of the town of Lillehammer.

[1] The village had its own sports team Tretten IL until 1990, when a merger created Øyer-Tretten IF.

The village is also the site of Tretten Church which serves the northern part of the municipality.

On 15 August 2022, the Tretten Bridge over the Gudbrandsdalslågen river completely collapsed;[3] it had beams of glued laminated timber and others of weathering steel.