Barbaise is located at an altitude of 209 metres some 16 km south-west of Charleville-Mézières and 30 km north-east of Rethel. Access to the commune is by the D3 road from Jandun in the east which passes through the centre of the commune and continues north-east to Warnécourt. Access to the village is by the D203 which branches off the D3 in the commune and goes south to the village. The commune is mostly farmland with forests in the north-east and north of the commune.
The Ruisseau de Barbileuse rises in the village and flows south to join the Vence south-west of Raillicourt.
In 2010 the commune had 105 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 1]
^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.