Argançon is located some 8 km east by north-east of Vendeuvre-sur-Barse and 8 km north-west of Bar-sur-Aube in the Orient Forest Regional Natural Park. Access to the commune is by highway D619 from Dolancourt in the north-east through the north of the commune to Magny-Fouchard in the west. Access to the village is by the D44 from Dolancourt passing through the village and continuing south to Spoy. There is also the D144 road from the village to the hamlet of Le Chanet in the north of the commune. Two thirds of the commune is farmland with the rest heavily forested in the east and the south.
The Landion river flows through the commune from south to north passing through the village and continuing north to join the Aube just north of Dolancourt.
In 2009 the commune had 101 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]
^At the beginning of the 21st century, the methods of identification have been modified by Law No. 2002-276 of 27 February 2002Archived 6 March 2016 at the Wayback Machine., 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 on 1 January 2009 and was based on the census of 2006.