At 48 square kilometres (19 sq mi) it is one of the largest municipalities of the Alta Segarra, and at one time was the most sparsely populated.

One holds that it derives from rubeus (coppery), possibly alluding to the red colour of the land and the rocks of the mountain on which was built the Castell de Rubió.

According to the second, Rubió derives from the Latin rufus (blond) through the name Rubione, a local landowner in the Roman Empire.

The coat of arms, granted on 12 February 1996, has on the inferior part a gules castle with a fleur-de-lis in the centre.

North of the Serra de Rubió is the Maçana River, a tributary of the Llobregat.

The Rubió wind farm, Catalonia's largest, consists of 50 windmills which can produce energy for 30,000 homes.

At the beginning of the 19th century, during the Peninsular War, the Serra de Rubió was a strategic point for the Igualadan resistance.