691 inhabitants for each km ²
Roa is located the administrative center of the Norwegian municipality Lunner, about 55 kilometers north of Oslo. Roa is located at the junction of Highway 35 after Hønefoss of the highway 4 to Gjøvik.
The Roa Station is an important railway junction: Here branches off the old route of the cable car, today's Roa - Hønefosslinje ( Jevnakerbanen ) of the Gjøvikbahn from to meet in Hønefoss on todays route the cable car. The station was opened in 1909 as part of the Oslo-Bergen connection, but in the beginning of the 21st century ride most passenger trains over Drammen, while freight trains use the shorter route via Roa.
In January 2011, lived in Roa 1,582 inhabitants.