Andelain is located some 24 km south-southeast ofSaint Quentin and 4 km east ofTergnier. It can be accessed by the D13 road fromCharmes in the northeast passing through the village and continuing toDeuillet in the southwest. The D1032 road also runs through the north of the commune from west to east and the D553 road cuts through the southwestern corner of the commune. Apart from the village the commune consists entirely of farmland with no other villages or hamlets.[3]
TheOise river forms a small part of the northwestern border of the commune and a stream flows through the northwestern part of the commune into the Oise river.[3]
TheChurch of Saint-Denis (12th century). is registered as an historical monument.[7] The Church contains several items that are registered as historical objects: