NORTHERN AUSTRALIA, a term indefinite but applied generally to that portion of the continent which lies north of the Tropic of Capricorn (c. 1,150,000 sq. miles= 0.386 or about of the whole territory), comprises the northern portions of Western Australia (364,00o sq. miles= 0.373 of the State), of the (former) Northern Territory (426,320 sq. miles = o.8i4) and of Queensland (359,000 sq. miles = 0.535). Except for a practi cally continuous belt of coastal lowlands—broader along and up the river valleys of the north-west and north and around the Gulf of Carpentaria (q.v.), narrow to the point of disappearance along the north-east—almost the whole of this area consists of table lands of 500-1,500 ft. general elevation with but few small and isolated higher areas in the west, north-west, north-east and central south. (See AUSTRALIA : Geomorphology.) Climate is thus the dominant factor and characteristic in this respect are prevailingly high temperature levels, F (c. 6o° in the central interior) and summer (monsoonal) rainfall: c. 6o in. along the north, sinking to 20 in. at about 18° lat. and to 10 in. and less farther inland. Thus, apart from the mineral wealth, of which a probably small part has so far been exploited, the chief economic possibilities would appear to be pastoral developfnent in the drier and more invigorating interior, tropical agriculture in the more humid lowlands and fishing—including pearl-oyster, etc., fishing (see BARRIER REEF)—around the coasts. The ulti mate commercial and strategic importance of certain parts of the coasts are probably also considerable.
The regional differentiation inherent in so vast an area will increasingly invalidate generalisations about it and the tropical portions of Queensland and Western Australia are best dealt with under those States (qq.v.). The area which was till recently called the Northern Territory is on a somewhat different basis, and as it also offers a fair average "cross-section" of northern Australia, a brief account of it is given here.
The area in question extends from the Western Australian to the Queensland border (Longs. 129°-138° E.) and from the north coast—including adjacent islands, e.g., Melville, Bathurst, Groote Eylandt—to the South Australian border (26° S. lat.) and covers 523,62o square miles in all. After a chequered history it was handed over by South Australia to the Commonwealth in 1911, and, as a result of further and on the whole unsuccessful expe rience, it was subdivided—in March, 1927, under the "Northern. Australia Act" of 1926—into North Australia and Central Aus tralia, lying respectively north and south of lat. 20° S., to be administered, from Newcastle Waters and Alice Springs (q.v.) respectively, as Commonwealth territories, each by a Govern ment Resident assisted by an Advisory Council of f our.
higher (sandstone) tableland of Arnhem Land and on the east and west the land rises gradually to the Barkly Tableland and the Kimberley plateau respectively. In the south the swell of the land forms (17°-20° S. lat.) an almost imperceptible watershed between the coastwards and inwards-flowing drainage. The coast is mostly low, sand-beaches and mangrove mud-swamps alternat ing with cliffy bluffs, but some fine natural harbours ("drowned" river-mouths) exist (cf. Port Darwin). There are two seasons, the wet (Nov.–May) and the dry, and the average ann. rainfall ranges from c. 4o in. in the north (Darwin: 62 in.) to 14 in. in the south. Temperatures are high, but the range is greater, the heat is drier and more bearable, and the winters are cooler towards the south (Darwin, ay. ann. temp., 85.7°-77.2° F; Daly Waters [300 miles inland], 88.2°-68.6° F [cf. Alice Springs inf.]). In the wet season the streams are mostly swollen, swift and liable to flood and wide areas in the valley bottoms are then under water while inland are lagoons and swamps (Lakes Woods, de Burgh, etc.). The Vic toria, Daly, Roper and McArthur are considerable streams but are normally navigable only in the dry season for small craft (4 ft. 6 in. draught; cargo capacity 35 tons). The valleys are often timbered and open forests occur in parts, but the prevailing vegetation is of the savanna type—grass with scattered trees— merging inland into poorer scrub with soft spinifex in the sandy south-western corner. From Camooweal (Queensland) to New castle Waters, in the upper Victoria River basin, and also south westwards towards Hall's Creek (Western Australia) are broad belts and patches ("many thousands of square miles") of open black-soil (limestone and volcanic) plains bearing first-class fodder grasses (Mitchell, Flinders, etc.) and edible scrubs and here are the principal cattle stations (e.g., Alexandra, Anthony's Lagoon, etc., on the Barkly Tableland; Wave Hill, etc., on the Victoria River). Surrounding these and occupying the bulk of the central belt are great expanses of more mixed country, fairly well grassed and watered and containing good patches. The sandy plateaux of the north and of the coastal margins have many well-grassed valleys and the swampy flats mentioned above. Lateritic and travertine incrustations, products of climatic and soil conditions, render considerable areas unproductive. Water is, generally speaking, available on the 'surface or in underground supplies and minerals are known to be widely distributed. The chief economic potentialities have been indicated. Efforts towards development have not hitherto been conspicuously successful and a summary of the present (5927) economic and social position will suffice.