The state electorate of Mirani has an approximate area of 72,000 km².

It is comprised of 75 suburbs including Alexandra, Alligator Creek, Armstrong Beach, Bakers Creek, Balberra, Baree, Benholme, Boulder Creek, Brightly, Broken River, Campwin Beach, Chelona, Dalma, Dalrymple Heights, Devereux Creek, Dows Creek, Dunnrock, Etna Creek, Eton, Eungella, Freshwater Point, Gargett, Garnant, Glendale and Glenlee plus parts of another 5 suburbs.

It is comprised of 38 localities including Alton Downs, Bajool, Bouldercombe, Bushley, Canoona, Carmila, Clairview, Clarke Creek, Collaroy, Crediton, Finch Hatton, Fletcher Creek, Glenroy, Gogango, Ilbilbie, Kalapa, Koumala, Kunwarara, Lotus Creek, Marlborough, Marmor, Midgee, Morinish, Morinish South and Mount Gardiner plus parts of another 5 localities.

It is comprised of the council of Rockhampton plus parts of Isaac, Livingstone and Mackay.

It is surrounded by the state electorates of Burdekin, Callide, Gladstone, Gregory, Keppel, Mackay, Rockhampton and Whitsunday.

It is comprised of parts of the federal electorates of Capricornia and Flynn.