 B. brownii occurs between Albany (35°S) and the Stirling Range (34°24'S) in the southwest of Western Australia, at the juncture of the Esperance Plains, Warren and Jarrah Forest biogeographic regions. This is the taxonomically richest area for Banksia, with 19 species, of which six are endemic, including B. brownii itself. It is cool and wet, with temperatures between four and 30°C (39 – 86°F) and rainfall of around 800 millimetres (31 in). The species occurs there in two distinct population clusters: southern populations occur among low woodland of Eucalyptus marginata (jarrah) in shallow, nutrient-poor white or grey sand over laterite; Stirling Range populations occur at altitudes of between 500 and 1100 metres (1640 – 3960 ft), among heath on rocky mountain slopes and tops, and in shale in gullies.
