Asnières-sur-Saône is on the bank of the Saône river some 15 km north of Mâcon and 50 km south of Chalons-sur-Saône. The commune can be accessed on the D18 road from Quart-d'Aval in the north-east to the village. The road continues south as the D1 road then turns south-east to Manziat. The D1E branches off in the south of the commune and goes south to Le Chateau. The commune consists entirely of farmland with no other villages or hamlets.
The Saône river forms the entire western border of the commune with no bridges across the river. A canal runs parallel to the river joining the river in the south and joining the Bief de la Jutane in the north which forms part of the northern border.
In 2010, the commune had 73 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 , 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.