Municipal governments in the region cooperate extensively in various fields: for example waste policy, shared public transport and a joint fire brigade.

The region contains Iceland's largest urban area by far, Greater Reykjavík (Icelandic: Stór-Reykjavík), a conurbation that includes parts of six out of seven municipalities of the region (Kjósarhreppur is all rural).

[3] Seven municipalities make up the Capital Region with Reykjavík being the most populated by far with 136,894 inhabitants.

Kjósarhreppur is the largest municipality by area (284 km2 (110 sq mi)) but is entirely rural and only has 269 inhabitants.

Statistics Iceland has defined contiguous urban areas which ignore municipal boundaries.