Léman was the name of a département of the First French Empire

First French Empire

The First French Empire , also known as the Greater French Empire or Napoleonic Empire, was the empire of Napoleon I of France...

. Its name is the French name of Lake Geneva

Lake Geneva

Lake Geneva or Lake Léman is a lake in Switzerland and France. It is one of the largest lakes in Western Europe. 59.53 % of it comes under the jurisdiction of Switzerland , and 40.47 % under France...

 (Lac Léman). It was formed in 1798, when the republic of Geneva

Geneva

Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...

 was occupied by the French. Léman also included districts that were previously part of the départements Mont-Blanc

Mont-Blanc (département)

Mont-Blanc was the name of a département of the First French Empire. It was named after Mont Blanc, the highest mountain in Western Europe. It was formed in 1792, when the Savoy region, was occupied by the French...

 (northern Savoy

Savoy

Savoy is a region of France. It comprises roughly the territory of the Western Alps situated between Lake Geneva in the north and Monaco and the Mediterranean coast in the south....

) and Ain

Ain

Ain is a department named after the Ain River on the eastern edge of France. Being part of the region Rhône-Alpes and bordered by the rivers Saône and Rhône, the department of Ain enjoys a privileged geographic situation...

 (around Gex

Gex, Ain

Gex is a commune in the Ain department in eastern France.It lies from the Swiss border and from Geneva. It is a sous-préfecture of Ain.-History:...

).

The capital of Léman département was Geneva

Geneva

Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...

. The département was subdivided into the arrondissement

Arrondissement

Arrondissement is any of various administrative divisions of France, certain other Francophone countries, and the Netherlands.-France:The 101 French departments are divided into 342 arrondissements, which may be translated into English as districts. The capital of an arrondissement is called a...

s of Geneva, Bonneville

Bonneville, Haute-Savoie

Bonneville is a commune in the Haute-Savoie department in the Rhône-Alpes region in south-eastern France.-Geography:Bonneville is on the A40 autoroute, roughly halfway between Geneva and Chamonix...

 and Thonon-les-Bains

Thonon-les-Bains

Thonon-les-Bains is a town in the Haute-Savoie department in the Rhône-Alpes region in south-eastern France. It is a sub-prefecture of the department.-History:...

. Its territory corresponds with the present Swiss

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

 canton of Geneva

Canton of Geneva

The Republic and Canton of Geneva is the French speaking westernmost canton or state of Switzerland, surrounded on almost all sides by France. As is the case in several other Swiss cantons The Republic and Canton of Geneva is the French speaking westernmost canton or state of Switzerland,...

 and parts of the present French départements Ain and Haute-Savoie

Haute-Savoie

Haute-Savoie is a French department in the Rhône-Alpes region of eastern France. It borders both Switzerland and Italy. The capital is Annecy. To the north is Lake Geneva and Switzerland; to the south and southeast are the Mont Blanc and Aravis mountain ranges and the French entrance to the Mont...

.

After the final defeat of Napoleon Bonaparte

Napoleon I of France

Napoleon Bonaparte was a French military and political leader during the latter stages of the French Revolution.As Napoleon I, he was Emperor of the French from 1804 to 1815...

 in 1815, the former republic of Geneva

Geneva

Geneva In the national languages of Switzerland the city is known as Genf , Ginevra and Genevra is the second-most-populous city in Switzerland and is the most populous city of Romandie, the French-speaking part of Switzerland...

 became a Swiss

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

 canton

Cantons of Switzerland

The 26 cantons of Switzerland are the member states of the federal state of Switzerland. Each canton was a fully sovereign state with its own borders, army and currency from the Treaty of Westphalia until the establishment of the Swiss federal state in 1848...

, and Savoy was returned to the Kingdom of Sardinia

Kingdom of Sardinia

The Kingdom of Sardinia consisted of the island of Sardinia first as a part of the Crown of Aragon and subsequently the Spanish Empire , and second as a part of the composite state of the House of Savoy . Its capital was originally Cagliari, in the south of the island, and later Turin, on the...

. The area around Gex returned to Ain département.