Abomsa is a town located in central Ethiopia within the Arsi Zone of the Oromia Region. It is situated at a latitude and longitude of 8°35′N 39°51′E with an altitude of 1,438 meters above sea level.
The town serves as the administrative center of Merti woreda. Historically, Abomsa functioned as the capital of Arba Gugu awrajja until 1995.