Arero is one of the woredas in the Oromia Region of Ethiopia. Part of the Borena Zone, Arero is bordered on the southwest by Dire, on the west by Yabelo, on the north by Hagere Mariam, on the northeast by the Guji Zone, on the east by the Somali Region, and on the south by Moyale; the Dawa River, the only river in this woreda, separates Arero from Odo Shakiso and Liben. Towns in Arero include Meta Gefersa.
The altitude of this woreda ranges from 750 to 1700 meters above sea level. A survey of the land in this woreda shows that 20% is arable (1.7% was under cultivation), 40.3% pasture, 1.6% forest, and the remaining 38.1% is considered swampy, mountainous or otherwise unusable. The forested area includes Arero State Forest, which covers about 10.65 square kilometers and is the most southerly of the high forests of Ethiopia, one of the few places in the Borena Zone with well-grown trees of Juniperus procera.Teff, corn, haricot bean and wheat are important crops in this woreda.
Industry in the woreda includes 2 grain mills; deposits of gold, molybdenum, cobalt and graphite are present but have not been commercially developed. There were 11 Farmers Associations with 7624 members and 4 Farmers Service Cooperatives; about 40% of the farmers are pastoralists. Arero has 260 kilometers of dry-weather roads, for an average road density of 24 kilometers per 1000 square kilometers. About 33.8% of the urban and 12.5% of the rural population has access to drinking water.