Agen is the prefecture of the Lot-et-Garonne department in Nouvelle-Aquitaine, Southwestern France. It lies on the river Garonne, 135 kilo…Agen is the prefecture of the Lot-et-Garonne department in Nouvelle-Aquitaine, Southwestern France. It lies on the river Garonne, 135 kilometres southeast of Bordeaux. In 2021, the commune had a population of 32,485.