The core area of Les Avellanes i Santa Linya is situated where the plain meets the mountain, bordering the valley of Àger via the heights of Montclús and confronting the municipalities of Camarasa and Os de Balaguer. Geographically, the eastern zone includes the valleys of the Sant Urbà and Ribera ravines up to the Camarasa reservoir, while the west is irrigated by the Farfanya river.

The municipality is well connected by the L-904 road, which links Balaguer to Àger, and is also crossed by the railway line connecting Lleida to La Pobla de Segur. Among its most prominent geographical features are the mountains of Montalegre, La Malera, and the highest peak of Mont-roig, Pala Alta.

Historically, Les Avellanes belonged to the lordship of Bellpuig de les Avellanes. Santa Linya, which encompassed an extensive territory in the 13th century, was under the domain of the counts of Urgell and later the viscount of Cardona. The annexation of Santa Linya to the municipality of Les Avellanes took place in 1970.

One of the most relevant monuments is the Monastery of Bellpuig de les Avellanes, founded in the 12th century, where the remains of the counts of Urgell are preserved. Furthermore, the nucleus of Tartareu features archaeological remains dating from the Neolithic to the Bronze Age, while Vilanova de la Sal is a medieval village founded by the counts of Urgell in the mid-12th century.

The municipal area is part of the renowned Montsec Route, defined by the majesty of the mountain range and crossed by the Noguera Pallaresa and Noguera Ribagorçana rivers, which have created the impressive gorges of Terradets and Mont Rebei, featuring landscapes rich in fauna and vegetation.