Västerås (/ˌvɛstərˈoʊs/ VEST-ər-OHSS, US also /-ˈɔːs/ -⁠AWSS,[4][5][6][7] Swedish: [vɛstɛrˈoːs] ⓘ) is a city in central Sweden on the shore of Lake Mälaren in the province of Västmanland, 100 kilometres (62 miles) west of Stockholm.

A castle commands the town from an eminence; it was captured by King Gustav I and rebuilt by him, and Eric XIV was confined there from 1573 to 1575.

During the riksdag assembly, the decision was made to convert Sweden into a Protestant state and to remove the power of the Catholic Church.

Rudbeckianska gymnasiet, the oldest gymnasium (secondary school) in Sweden, was built in Västerås by Johannes Rudbeckius in 1623.

To this effect, the city has started using a designed logo as branding in some official contexts, partially replacing the coat of arms, as well as rebuilding several old harbor areas to make them more attractive to live in.

Until 2017, Västerås hosted Power Big Meet, an annual event for owners and enthusiasts of classic American cars.

This early electrification encouraged ASEA, a large electricity equipment manufacturer, to concentrate its operations in Västerås, shifting focus away from Arboga.

ABB in Västerås maintains production, e.g. robots and drive systems for industry, high-voltage direct current transmission and power grids.

On 11 April 2014, after the Russian annexation of Crimea, the contract with Energoatom for the South Ukraine Nuclear Power Plant was extended through 2020.

[18] Mälarenergi AB is a city-owned district heating and electric power provider for Västerås and surrounding area.

Other major industries include Bombardier Transportation, which is active in railway business with production of propulsion systems for trains with worldwide customers, GE Power Sweden, Enics, Quintus Technologies AB (high pressure metal working and material densification equipment for the manufacturing industry) and Northvolt AB which designs, develops and manufactures lithium-ion battery cells and complete battery systems for electric vehicles, heavy transport, mining, and energy industries, as well as portable devices.

One of the historical reasons that made Västerås a city is its trading-friendly location by the river Svartån and lake Mälaren.

The city remains one of the main logistical centers in Sweden due to its central location in the densely populated region Mälardalen and favourable infrastructure connections with railways, waterways and highways.