Geography

Paris is located in the north-bending arc of the river Seine and includes two islands, the Île Saint-Louis and the larger Île de la Cité, which form the oldest part of the city. Overall, the city is relatively flat, and the lowest elevation is 35 metres (114 ft) above sea level.
Paris has several prominent hills, of which the highest is Montmartre at 130 m (426 ft).

Paris, excluding the outlying parks of Bois de Boulogne and Bois de Vincennes, covers an oval measuring 86.928 square kilometres (33.56 square miles) in area.

The city's last major annexation of outlying territories in 1860 not only gave it its modern form, but created the twenty clockwise-spiralling arrondissements (municipal boroughs). From the 1860 area of 78 km² (30.1 sq mi), the city limits were expanded marginally to 86.9 km² (34 sq mi) in the 1920s.
In 1929 the Bois de Boulogne and Bois de Vincennes forest parks were officially annexed to the city, bringing its area to the present 105.397 km² (40.69 sq mi).

Paris' real demographic size, or unité urbaine, extends well beyond the city limits, forming an irregular oval with arms of urban growth extending along the Seine and Marne rivers from the city's southeast and east, and along the Seine and Oise rivers to the city's northwest and north.

Beyond the main suburbs, population density drops sharply; a mix of forest and agriculture dotted with a network of relatively evenly dispersed éparpillement of satellite towns, this couronne périurbaine commuter belt, when combined with the Paris agglomeration, completes the Paris aire urbaine (or Paris urban area, a sort of metropolitan area) that covers an oval 14,518 km² (5,605.5 sq mi) in area, or about 138 times that of Paris itself.