Austria is a federal republic made up of nine states, known in German as Länder (singular Land). Since Land is also the German word for "country", the term Bundesländer ("federation states"; singular Bundesland) is often used instead to avoid ambiguity. The Constitution of Austria uses both terms. In English, the term (Bundes)land is commonly rendered as "state" or "province".
The majority of the land area in the states of Upper Austria, Lower Austria, Vienna, and Burgenland is situated in the Danube valley and thus consists almost completely of accessible and easily arable terrain. The other five states, in contrast, are located in the Alps and thus are comparatively unsuitable for agriculture. Their terrain is also relatively unfavourable to heavy industry and long-distance trade. Accordingly, the population of what now is the Republic of Austria has been concentrated in the former four states since prehistoric times. Austria's most densely populated state is the city-state of Vienna, the heart of what is Austria's only metropolitan area. Lower Austria ranks fourth with regard to population density even though containing Vienna's suburbs; this is due to large areas of land being predominantly agricultural. The alpine state of Tyrol, the less alpine but geographically more remote state of Carinthia, and the non-alpine but near-exclusively agricultural state of Burgenland are Austria's least densely populated states. The wealthy alpine state of Vorarlberg is something of an anomaly due to its small size, isolated location and distinct Alemannic culture.
The following ranked list of Austrian states cites official Statistik Austria population on 1 January 2015.Areas are given in square kilometres, population density is expressed in inhabitants per square kilometre. For the purpose of the above list, a city is a community defined to be a city by Austrian law; a town is a community not defined to be a city. Many of Austria's cities have population figures on the order of ten thousand inhabitants; some are even smaller.