Agiaon is 30 km to the south of Arrah, in Bhojpur District of Bihar. It is perched at an altitude of 206 ft above sea level, on the western banks of the Son River.
Major pilgrim spots in the neighborhood are Sahasra Kuta Chaitalya and Aranya Devi Temple dedicated to Aranya Devi.
Agiaon is close to Garhani (9 km to the north-west), Panwar (4 km to the north), Sandes (13 km to the north-east) and Ekwari (6 km to the south).
Nearest airport is Patna Airport, approximately 42 km to the north-east.
Agiaon is served by Arrah Railway Station.
