Argein is located some 12 km south-west of Saint-Girons just a kilometre west of Audressein. Access to the commune is by the D618 road from Audressein in the east passing through the centre of the commune and the village and continuing west to Aucazein. Apart from the village there is also the hamlet of Viellot. The centre of the commune is the valley of the Bouigane oriented east-west where the village lies. In the valley there is some farmland however the rugged north and south of the commune is heavily forested.
The Buouigane river flows along the central valley east to join the Léz at Audressein. Some tributaries rise in the commune to join the Bouigane including the Ruisseau d'Auriech and the Ruisseau de Sol.
In 2009 the commune had 176 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 towns that have a sample survey every year.[Note 1]
The Parish Church of Saint Peter is an old Romanesque church from the 12th century and now an integral part of a church originally built in the 9th century. The original semicircular Apse forms the south aisle of the present building. There is an altar bearing a very ancient inscription (prior to the 4th century) depicted again in the south wall of the church. The Church contains many items that are registered as historical objects:
Honoré Laffont, born 6 October 1901 at Argein and died on 14 February 1975. An international Rugby player (1st time in 1926 against Wales). He was twice a finalist in the championship of France with RC Narbonne (1932 and 1933). He played scrum half (1.65m, 62kg). He was also coach for RC Narbonne.
^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.