Balaguères is located some 4 km north-east of Audressein and 12 km south-west of Saint-Girons in the Parc naturel régional des Pyrénées ariégeoises. The north-west border of the commune is also the departmental border between Ariège and Haute-Garonne. Access to the commune is by the D618 road from Engomer in the east which passes through the south of the commune and continues south-west to Audressein. Access to the main village of Alas is by the D204A from Engomer and several local roads. The D204 goes north-west from the village through the hamlet of Agert to the hamlet of Balagué in the commune. The commune is farmland in the valley and forested on the mountain slopes.
The Lez river flows through the south of the commune and the village from south-west to east and continues east then north-east to join the Salat at Saint-Girons. The Ruisseau de Lachein flows from the north-west through the commune, gathering several tributaries, to join the Lez at the village.
Balagué, Agert, and Alas were all part of the lordship of Aspet in the 12th century together with Engomer, Montgauch, Bareilles, and Mauvezin de Prat. This lordship became a powerful Barony in the Middle Ages. On 12 December 1642 Guy d'Encausse, Lord of Labastide (near Rieucazé) purchased Alas-Balagué and gave it to Jean-Jacques de Solan. By decree in April 1667 King Louis XIV ordered the purchase of 18 parishes that had been committed in 1642 and 1643. They all returned to the Crown lands of France. Later, however, some were sold again (Castelbiague, Pointis-Inard, Alas-Agert-Balagué). Others remained in paréage[Note 1] with the king: Affis (His), Arbas, Ganties, Mauvezin, Montastruc, and Rouède. The rest remained permanently in the hands of the king as sole lord: Aspet, Chein, Escaich, Estadens, Montgauch-Bareilles, and Saleich.
In 2010 the commune had 199 inhabitants. The evolution of the number of inhabitants is known from the population censuses conducted in the commune since 1793. From the 21st century, a census of communes with fewer than 10,000 inhabitants is held every five years, unlike larger communes that have a sample survey every year.[Note 2]
^A feudal contract between two or more lords giving them equal rights
^At the beginning of the 21st century, the methods of identification have been modified by Law No. 2002-276 of 27 February 2002, the so-called "law of local democracy" and in particular Title V "census operations" allows, after a transitional period running from 2004 to 2008, the annual publication of the legal population of the different French administrative districts. For communes with a population greater than 10,000 inhabitants, a sample survey is conducted annually, the entire territory of these communes is taken into account at the end of the period of five years. The first "legal population" after 1999 under this new law came into force in 1 January 2009 and was based on the census of 2006.