Barenton-Cel is located some 10 km north by north-east of Laon and 40 km south-east of Saint-Quentin. It can be accessed by the D547 road from Verneuil-sur-Serre in the north-east continuing southwest through the commune and the village to Aulnois-sous-Laon in the south-west. There is also the D545 road from Barenton-Bugny on the south-eastern border. The commune consists entirely of farmland with no other villages or hamlets.
The Ru des Barentons stream forms the south-eastern border of the commune and flows north-east to join the Souche river in the north.
In 2010 the commune had 136 inhabitants. The evolution of the number of inhabitants is known through the population censuses conducted in the commune since 1793. From the 21st century, a census of municipalities 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 2002 , the so-called "law of local democracy" and in particular Title V "census operations" which allow, after a transitional period running from 2004 to 2008, the annual publication of the legal population of the different French administrative districts. For municipalities with a population greater than 10,000 inhabitants, a sample survey is conducted annually, the entire territory of these municipalities 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.