European route E 21 is a series of road

Road

A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...

s in Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

, part of the United Nations

United Nations

The United Nations is an international organization whose stated aims are facilitating cooperation in international law, international security, economic development, social progress, human rights, and achievement of world peace...

 International E-road network

International E-road network

The international E-road network is a numbering system for roads in Europe developed by the United Nations Economic Commission for Europe . The network is numbered from E 1 up and its roads cross national borders...

.

It runs from Metz

Metz

Metz is a city in the northeast of France located at the confluence of the Moselle and the Seille rivers.Metz is the capital of the Lorraine region and prefecture of the Moselle department. Located near the tripoint along the junction of France, Germany, and Luxembourg, Metz forms a central place...

, France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

 to 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...

, Switzerland

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....

. It meets the European route E 25

European route E25

European route E 25 is a north-south European route from Hoek van Holland in the Netherlands to Palermo in Italy which includes ferry crossings from Genoa to Bastia , from Bonifacio to Porto Torres and from Cagliari to Palermo .It passes through the following cities:Hoek van Holland –...

, the E 50

European route E50

European route E 50 is an A-type east–west connection across the European continent. It connects the key naval port of Brest France with Makhachkala, on the Caspian Sea in the Russian republic Dagestan....

 and the E 411

European route E411

European route E411 is a European route in Belgium connecting Brussels to Aubange, a town at the border between Belgium, France and Luxembourg via Namur and Arlon. The E411 starts in the municipality of Auderghem along the Beaulieu metro station, crosses the municipality on a viaduct, then crosses...

 at Metz, from where it departs. On its way to Geneva, it crosses the E 23

European route E23

European route E 23 is a series of roads in Europe, part of the United Nations International E-road network.-Route through Switzerland:A9 France-Vallorbe-Orbe-A1A1 Orbe-LausanneA1A Lausanne-Lausanne Centre-Links with other European routes:...

 at Nancy, and also passes through Dijon

Dijon

Dijon is a city in eastern France, the capital of the Côte-d'Or département and of the Burgundy region.Dijon is the historical capital of the region of Burgundy. Population : 151,576 within the city limits; 250,516 for the greater Dijon area....

. It enters Switzerland

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....

 soon after and links with the E 25

European route E25

European route E 25 is a north-south European route from Hoek van Holland in the Netherlands to Palermo in Italy which includes ferry crossings from Genoa to Bastia , from Bonifacio to Porto Torres and from Cagliari to Palermo .It passes through the following cities:Hoek van Holland –...

, the E 62

European route E62

The European route E 62 is a road in Europe and a part of the United Nations International E-road network. Approximately long, it connects the French Atlantic port city of Nantes to Genoa, largest of Italy's port cities. Between France and Italy it also passes through Switzerland, via...

 and the E 712 at 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...

, allowing further travel through Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

. It is 458 km (284.6 mi) long in total.