It is located in the south-western part of Slovakia and has an area of 2,053 km² and a population of 603,699 (2005). The region has a dual nature - the Little Carpathians starting in Bratislava and going steadily north-east separating two lowlands, the Záhorie lowland in the west and the fertile Danubian Lowland in the east, which grows mainly wheat and maize. Major rivers in the region are the Morava River, the Danube and the Little Danube, the latter with the Danube encircling the Žitný ostrov in the south-east. There are three protected landscape areas within the territory of the region: the Little Carpathians, Záhorie and Dunajské luhy. The region borders Trnava Region in the north and east, Győr-Moson-Sopron county in Hungary in the south, Burgenland in Austria in the south-west and Lower Austria in the west.
The first known permanent settlement of the area of today's Bratislava began with the Linear Pottery Culture, around 5000 BC in the Neolithic era. Around 200 BC, the Celtic Boii tribe established an oppidum on the place of today's Bratislava Castle The Romans established their camp Gerulata on the right bank of the Danube in the 1st century and remained there until the 4th century. The area was part of the Principality of Nitra and later of the Great Moravia in the 9th century. From the 10th century onwards, it became part of the Principality of Hungary (later called Kingdom of Hungary) and almost wholly became part of the Pozsony county (with the exception of three villages south of Bratislava which were part of the Moson county). After break-up of Austria-Hungary in 1918, the county continued to exist in Czechoslovakia, but was abolished in 1928 and replaced with a new territorial unit called "Slovak Land". During the WWII Slovak Republic the Bratislava county was restored, albeit with somewhat modified borders. After restoration of Czechoslovakia, the pre-breakup state was restored. In 1949-1960 a unit named Bratislava Region used to exist, but was replaced in 1960 with the Western Slovak Region (except from 1 July 1969 to 28 December 1970; Bratislava was partly separate from 1968, and since 1971 was a separate region). After abolition of the regions in 1990, the current system was introduced in 1996. After the administrative regions became autonomous in 2002, it is governed by the Bratislava Self-Governing Region.
Despite being the smallest region of Slovakia, it isn't the least populated. The largest city is Bratislava (425,459) and the second-largest is Pezinok (21,334). The region has a high level of urbanization (83.2%). According to the 2001 census, there were 599,015 inhabitants in the region, with most of them being Slovaks (91.2%), with a minority of Hungarians (4.6%) and Czechs (1.6%).