The federal electorate of Mcewen has an approximate area of 4,600 km².
It is comprised of 66 suburbs including Arthurs Creek, Bend Of Islands, Beveridge, Bolinda, Broadford, Bulla, Bullengarook, Bylands, Cherokee, Chintin, Christmas Hills, Clarkefield, Cobaw, Cottles Bridge, Darraweit Guim, Donnybrook, Doreen, Eden Park, Forbes and Gisborne plus parts of another 9 suburbs.
It is comprised of the localities of Clonbinane, Glenaroua, Lancefield, Puckapunyal, Sunbury, Tallarook, Tooborac and Whiteheads Creek plus parts of Avenel and Flowerdale.
It is comprised of parts of the councils of Hume City, Macedon Ranges Shire, Mitchell Shire, Nillumbik Shire and Whittlesea City.
It is comprised of parts of the state electorates of Eildon, Euroa, Macedon, Mill Park, Sunbury, Thomastown, Yan Yean and Yuroke.
It is surrounded by the federal electorates of Ballarat, Bendigo, Calwell, Casey, Gorton, Indi, Jagajaga, Menzies, Murray and Scullin.