Balnot-sur-Laignes is located some 35 km south-east of Troyes and 10 km south of Bar-sur-Seine. Access to the commune is by the D452 road from Polisy in the north which passes down the eastern side of the commune just east of the village and continues south to Les Riceys. The D26 comes from Neuville-sur-Seine in the east and passes through the village continuing south-west to Bagneux-la-Fosse. The D184 from Avirey-Lingey passes through the western arm of the commune going north-west to join the D36. The commune is farmland in the east and west with a belt of dense forest through the centre.
The Laignes river forms the eastern border of the commune as it flows north to join the Seine at Polisy.
In 2010 the commune had 159 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.