Boulogne-sur-Seine

Boulogne-Billancourt
The church of Our Lady of Boulogne-Billancourt
Coat of arms
Paris and inner ring départements
Coordinates: 48°50′07″N 2°14′27″E / 48.83520°N 02.2409°E / 48.83520; 02.2409Coordinates: 48°50′07″N 2°14′27″E / 48.83520°N 02.2409°E / 48.83520; 02.2409
Country	France
Region	Île-de-France
Department	Hauts-de-Seine
Arrondissement	Boulogne-Billancourt
Canton	Boulogne-Billancourt-1 and 2
Intercommunality	Grand Paris
Government
• Mayor (2008–2020)	Pierre-Christophe Baguet
Area1	6.17 km2 (2.38 sq mi)
Population (2012)2	117,126
• Density	19,000/km2 (49,000/sq mi)
Time zone	CET (UTC+1)
• Summer (DST)	CEST (UTC+2)
INSEE/Postal code	92012 /92100
Elevation	28–40 m (92–131 ft)
1 French Land Register data, which excludes lakes, ponds, glaciers > 1 km² (0.386 sq mi or 247 acres) and river estuaries. 2Population without double counting: residents of multiple communes (e.g., students and military personnel) only counted once.

¹ French Land Register data, which excludes lakes, ponds, glaciers > 1 km² (0.386 sq mi or 247 acres) and river estuaries.

Boulogne-Billancourt (French pronunciation: ​[bu.lɔɲ.bi.jɑ̃.kuʁ]; often colloquially called simply Boulogne) is a commune in the western suburbs of Paris, France. It is located 8.2 km (5.1 mi) from the centre of Paris. Boulogne-Billancourt is a subprefecture of the Hauts-de-Seine department and the seat of the Arrondissement of Boulogne-Billancourt.

With an average household income in 2013 of €47,592, nearly twice the French average of €25,548, Boulogne-Billancourt is one of the wealthiest cities in France.

Boulogne-Billancourt is the most populous suburb of Paris and one of the most densely populated municipalities in Europe. Formerly an important industrial site, it has successfully reconverted into business services and is now home to major communication companies headquartered in the Val de Seine business district.

The original name of the commune was Boulogne-sur-Seine (meaning "Boulogne upon Seine").

Before the 14th century, Boulogne was a small village called Menuls-lès-Saint-Cloud (meaning "Menuls near Saint-Cloud"). In the beginning of the 14th century, King Philip IV of France ordered the building in Menuls-lès-Saint-Cloud of a church dedicated to the virgin of the sanctuary of Boulogne-sur-Mer, then a famous pilgrimage center in northern France. The church, meant to become a pilgrimage centre closer to Paris than the distant city of Boulogne-sur-Mer, was named Notre-Dame de Boulogne la Petite ("Our Lady of Boulogne the Minor"). Gradually, the village of Menuls-lès-Saint-Cloud became known as Boulogne-la-Petite, and later as Boulogne-sur-Seine.