As of April 1, 2006 population data, the city has an estimated population of 53,599 and the density of 382 persons per km². The total area is 140.21 km².
Hyakuri Airfield, a Japan Air Self-Defense Force base, is located in Omitama. A new civil-aviation airport with domestic service to Naha, Fukuoka, Osaka, and Sapporo is being constructed at Hyakuri and will begin service in 2009 in the Ogawa section of Omitama, when it will operate as Ibaraki Airport.