3,317 (Dec 31, 2008)
Cossonay is a municipality in the canton of Vaud in Switzerland. It is the seat of the district of Morges.
Cossonay has both Roman ruins and medieval graves. The first documentation of the settlement dates from 1096 under the name Cochoniacum. In 1164, this appears as Cosonai, and in 1228 as Cossonai.
Ulrich von Cossonay gave the village church to the monastery in Romainmotier in 1096. In 1224, it passed to the Benedictine monastery in Lutry, which built a priory in the second half of the 13th century. The town wall, built in the 11th century, was rebuilt and extended in the 13th and 14th centuries. The Barons of Cossonay ruled over a territory from La Chaux to Boussens and from Dizy to Gollion.
Cossonay received city rights in 1264. A fire near the end of the 14th century destroyed much of the town and the town archives. In 1421, the town passed to the house of Savoy.
When the canton of Vaud was conquered by the Bernese in 1536, the town came under the administration at Morges. From 1798 to 1803, Cossonay was part of the canton of Leman in the Helvetic Republic, which was transformed into the canton of Vaud by the mediation of Napoleon. The district of Cossonay was formed in 1798, and the municipality has been its capital since its inception.
Cossonay lies at an elevation of 562 m (1,844 ft) and 14 km (8.7 mi) northwest of Lausanne. The town stretches across the high plateau west of the Venoge, about 130 m (430 ft) above the valley floor, in the Gros de Vaud in the middle of the canton of Vaud.
The municipality is the breadbasket of Vaud. The eastern boundary is the Venoge. In the south, it reaches down to the valley of the Valezard, and in the north to Pre Defour. On the west, lies the forest of Sepey, in which the highest point of the municipality lies at an elevation of 620 m. Here lies the Etang du Sepey, which is a lake formed by an earlier quarry.
Cossonay has an area, as of 2009, of 8.29 square kilometers (3.20 sq mi). Of this area, 5.15 km2 (1.99 sq mi) or 62.1% is used for agricultural purposes, while 1.91 km2 (0.74 sq mi) or 23.0% is forested. Of the rest of the land, 1.16 km2 (0.45 sq mi) or 14.0% is settled (buildings or roads), 0.01 km2 (2.5 acres) or 0.1% is either rivers or lakes and 0.01 km2 (2.5 acres) or 0.1% is unproductive land.
Of the built up area, industrial buildings made up 1.2% of the total area while housing and buildings made up 7.4% and transportation infrastructure made up 4.2%. Out of the forested land, 20.7% of the total land area is heavily forested and 2.3% is covered with orchards or small clusters of trees. Of the agricultural land, 50.4% is used for growing crops and 11.1% is pastures. All the water in the municipality is in lakes.
The municipality was the capital of the Cossonay District until it was dissolved on 31 August 2006, and Cossonay became part of the new district of Morges.
The municipality is located on a plateau, that rises steeply about 130 m (430 ft) above the Venoge river. On the plateau, it consists of the village of Cossonay-ville and the hamlets of Allens. The area of Grands Moulins, the cable works of Cossonay, the train station and the settlement of Cossonay-Gare are at the foot a hill that lies in the municipality of Penthalaz.
The surrounding municipalities are Penthalaz, Gollion, Senarclens, La Chaux, Dizy, and Lussery-Villars, all in the same district.