Piera is part of the Anoia region and is its largest municipality. It borders to the north with Castellolí and el Bruc, to the south with Sant Sadurní d'Anoia, to the east with Masquefa, to the west it borders with Cabrera d'Igualada, to the northeast with Hostalets de Pierola, to the northwest with the terms of Pobla de Claramunt and Vallbona d'Anoia, the southeast with Sant Llorenç d'Hortons and the southwest with Torrelavit.
