While most of it is classified as a motorway (highway), part of it (in the Sonian Forest) is merely an express route.

It crosses the three regions of Belgium: its main part (51.7 kilometres (32.1 mi)) is situated in Flanders, whereas Wallonia comprises 18.2 kilometres (11.3 mi) of the total stretch and 5.5 kilometres (3.4 mi) is on Brussels territory.

Going clockwise from there, the ring then crosses the municipalities of City of Brussels, Vilvoorde, Machelen, Zaventem, Kraainem, Wezembeek-Oppem, Tervuren, Auderghem/Oudergem, Watermael-Boitsfort/Watermaal-Bosvoorde, Hoeilaart, Waterloo, Braine-l'Alleud, Braine-le-Château, Halle, Beersel, Drogenbos, Forest, Sint-Pieters-Leeuw, Anderlecht, Dilbeek, Asse and Wemmel.

In all the ring crosses fifteen municipalities in Flanders, five in the Brussels Region, and three in Wallonia.

As well as having eight interchanges with other highways, the Brussels Ring has twenty-seven ramps (junctions), numbered counterclockwise from 1 to 27: