According to 2005 Japanese Census data, the district has a population of 97,537 and a density of 1,045.73 persons per km2. The total area is 93.10 km2.
The word roots "machi" and "chō" (both written as 町) mean "town." Onga is the only town in Fukuoka Prefecture for which 町 is pronounced "chō." For all other towns it is pronounced "machi."