Aubigny-aux-Kaisnes is located some 15 km south-west of Saint-Quentin and 5 km north-east of Ham. It can be accessed by road D930 which runs north-east from Ham and inside the north-western border of the commune towards Saint-Quentin. The D34 road also comes from Foreste in the north-west through the village and continuing to Bray-Saint-Christophe in the east. There is also a country road heading west from the village to Villers-Saint-Christophe. The commune consists entirely of farmland with no other villages or hamlets.
In 2010 the commune had 242 inhabitants. The evolution of the number of inhabitants is known through the population censuses conducted in the town 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 Archived 2016-03-06 at the Wayback Machine., 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.