The Commune of Brenna is situated in the south-eastern part of the Cieszyn County, which is part of the Province of Silesia, at the altitude of 420 m above the sea level. The commune consists of three villages: Brenna, Górki Wielkie and Górki Małe. They occupy the total area of 95.4 km²; in February 2016 the commune was inhabited by the population of about 10,900 people.
In the south-west Brenna borders on Skoczów, in the north-east – on the communes of Jasienica, Jaworze and on the town of Bielsko-Biała (on the mountain ridges of Błatnia – Stołów – Trzy Kopce). In the east it borders on Szczyrk (by the ridge of the mountain range from Trzy Kopce through Karkoszczonka Pass, Beskid Węgierski to Salmopolska Pass), in the south – on the town of Wisła and in the west – on the town of Ustroń.
Brenna itself is situated in the valley of the Brennica river (a right tributary of the Vistula). The village of Brenna consists of the following parts: Brenna Węgierski, Brenna Lachy, Brenna Bukowa, Nad Potokiem, Chrobaczy, Brenna Hołcyna, Brenna Centrum, Brenna Leśnica, Brenna Pinkas, Brenna Spalona.