Banneville-sur-Ajon is located some 20 km south-west of Caen and 7 km south-east of Villers-Bocage. Access to the commune is by the D121A from Saint-Agnan-le-Malherbe in the south which passes through the centre of the commune and the village and continues north to join the D8. The D171 from Landes-sur-Ajon to Préaux-Bocage passes through the north-east of the commune. Apart from the village there are the hamlets of La Fêterie in the south and Gournay in the north. The commune is almost all farmland.
The Ajon river flows through the commune from south-east to north-west continuing to join the Odon south-west of Le Locheur. The Orgeuil river rises in the south of the commune and flows north-east through the length of the commune to join the Ajon. The Ruisseau de la Rette flows from the south to join the Orgeuil.
In 2010 the commune had 379 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]
The Chapel of Saint-Clair (13th century) is registered as an historical monument. The church is built on a simple rectangular plan. On the tympanum of the south portal there is a figure in bas-relief of Saint Samson on his throne, and inside is a statue of Saint Clair.
The Church of Saint-Melaine is in neo-Gothic style from the late 19th century.
A replica of the grotto of Lourdes was built at a place called Le Village at the end of the Second World War.
^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 on 1 January 2009 and was based on the census of 2006.