The Westerpark (English: Western Park) is a public urban park in Amsterdam, Netherlands. The former borough (stadsdeel) of Westerpark is named after the park, as is the current neighborhood.

The verdant space of the former Westergasfabriek gasworks along Haarlemmerweg has become a place for cultural avant-garde businesses and events.

Up until the early seventeenth century, the Haarlemmerdijk (also called Spaarndammerdijk) constitutes the only connection between Haarlem and Amsterdam. The dike serves as protection against the IJ, but is subject to breakthroughs and floods. At the north of the dike lies a polder, which is the location of today's Westerpark. Its name, Overbraker Binnenpolder, probably refers to its frequent floods. A few farms are built along this dike between Amsterdam and Sloterdijk, then the first village on the road to Haarlem.

In the mid-19th century, Amsterdam struggles with the consequences of the Industrial revolution and the growth of its population. The increasing pollution and deteriorating hygiene conditions lead the city to consider the creation of parks and gardens around the city center. In 1845, Amsterdam's first municipal park, the Westerplantsoen (Western Garden), is created on the Overbraker Binnenpolder.

This first park is appreciated by the local population. Ton Heijdra notes:

There is enthusiasm for this new park, especially in the summer when it hosts theater performances. When they are thirsty, people can enjoy the Welgelegen tavern, on the Bogt stronghold, in the middle of the park. Welgelegen has a leafy garden and a music temple where performances are often held.

The experience, however, is short-lived: in 1869, the park is eliminated to make way for the railroads and canals, most notably the Westerkanaal that connects the Singelgracht and the Haarlemmertrekvaart to the IJ.

In October 1866, city engineer Jacob van Niftrik submitted his expansion plan for Amsterdam to the alderman for Public Works. This plan recommends the creation of several major parks around the city, but does not include the future Westerpark.

This plan is deemed too ambitious and costly and is rejected by the city council. As a result, the city's director of works, Jan Kalff, is asked to propose a more pragmatic plan, that would "synthesize developments that were underway, rather than steer developments itself".

At that time, the plan for a major extension of Amsterdam, primarily meant for the elite, had given way to a more moderate plan, drawn up by J. Kalff, who also made room for the middle class and even labourers. At the fringes of the belt, on space not suitable for the construction of houses, he designed two parks - the Oosterpark (East park) and the Westerpark (West park).

The original Westerpark is designed in 1890 by landscape architect Leonard Springer. While Westerpark was initially meant to be larger (around 10 hectares), its area is limited by the decision of the city to set up a gas plant, limiting its area to 5.63 hectares.

In 1883, the city grants a concession to the Imperial Continental Gas Association to create a plant that would produce town gas for street lighting. The buildings are designed by architect Isaac Gosschalk in the then-popular Dutch neo-renaissance style under the supervision of J. Pazzani, director of the new gas plant, who would decide on the location of the various buildings. This collaboration was intended to create a complex that would be both functional and aesthetically pleasing.

At the time, the site includes several coal storage areas, treatment plants and office buildings that stands in a U-shape around an imposing water tower:

The site was designed as follows: two treatment buildings were built parallel to the Haarlemmertrekvaart built; two coal sheds and two distilleries were built along the train track; between the distilleries and the purification buildings were some external buildings, such as a boiler house and a pump building, and a water tower was located immediately north. There were also some lonely constructions around the site such as an ammonia factory and the board houses. The porter's building, offices and engineering houses were situated along the eastern edge. This part of the site differed from the rest in character, because it housed the administrative functions.

The gas produced from coal is stored in large gas containers, two of which are still visible today The city puts an end to the concession in 1898, taking over the plant and added an additional coke gas plant.

After the second world war, the plant become gradually unnecessary with the extraction of natural gas in the North sea and the discovery of the Groningen gas field.

The production of coal gas is interrupted in 1960, leading to the demolition of several buildings that have become useless. The gas plant keeps producing city gas until 1967, and stops operating altogether after this date.