Trélex is a small village in the district of Nyon in the canton of Vaud in Switzerland.

Nyon is a municipality in Nyon District in the canton of Vaud in Switzerland. It is located some 25 kilometers north east of Geneva's city centre, and since the 1970s it has become part of the Geneva metropolitan area. It lies on the shores of Lake Geneva and is the seat of Nyon District. The town has a population of 21,718 and is famous in the sporting world for being the headquarters of the Union of European Football Associations (UEFA) and the European Club Association (ECA). It is connected to the rest of Switzerland by way of the Route Suisse, the A1 Motorway and the railways of the Arc Lémanique.