Liverpool is a port city and metropolitan borough in Merseyside, England. It is situated on the eastern side of the Mersey Estuary, near the Irish Sea, 178 miles (286 km) north-west of London. It had a population of 508,961 in 2024 and is the administrative, cultural and economic centre of the Liverpool City Region, a combined authority area with a population of over 1.5 million.

Established as a borough in Lancashire in 1207, Liverpool became significant in the late 17th century when the Port of Liverpool was heavily involved in the Atlantic slave trade. The port also imported cotton for the Lancashire textile mills, and became a major departure point for English and Irish emigrants to North America. Liverpool rose to global economic importance at the forefront of the Industrial Revolution in the 19th century and was home to the first inter-city railway, the first non-combustible warehouse system (the Royal Albert Dock), and a pioneering elevated electrical railway; it was granted city status in 1880 and was moved from Lancashire to the newly created county of Merseyside in 1974. It entered a period of decline in the mid-20th century, which was largely reversed after the European Union selected it as the European Capital of Culture for 2008, reportedly generating over £800 million for the local economy within a year.

The economy of Liverpool is diverse and encompasses tourism, culture, maritime, hospitality, healthcare, life sciences, advanced manufacturing, creative and digital sectors. The city is home to the UK's second highest number of art galleries, national museums, listed buildings, and parks and open spaces, behind only London. It is often used as a filming location due to its architecture and was the fifth most visited UK city by foreign tourists in 2022. It has produced numerous musicians, most notably the Beatles, and recording artists from the city have had more UK No. 1 singles than anywhere else in the world. It has also produced numerous academics, actors, artists, comedians, filmmakers, poets, scientists, sportspeople, and writers. It is the home of Premier League football teams Everton and Liverpool. The world's oldest still-operating main line railway station, Liverpool Lime Street, is in the city centre; it is also served by the underground Merseyrail network. The city's port was the fourth largest in the UK in 2023, with numerous shipping and freight lines having headquarters and offices there.

Residents of Liverpool are formally known as Liverpudlians but are more often called Scousers in reference to scouse, a local stew made popular by sailors. The city's distinct local accent is also primarily known as Scouse. Its cultural and ethnic diversity is the result of attracting immigrants from various areas, particularly Ireland, Scandinavia, and Wales; it is also home to the UK's oldest black community and Europe's oldest Chinese community, as well as the first mosque in England.

The name comes from the Old English lifer, meaning thick or muddy water, and pōl, meaning a pool or creek, and is first recorded around 1190 as Liuerpul. According to the Cambridge Dictionary of English Place-Names, "The original reference was to a pool or tidal creek now filled up into which two streams drained". Other origins of the name have been suggested, including "elverpool", a reference to the large number of eels in the Mersey. The adjective "Liverpudlian" was first recorded in 1833.

In the Middle Ages, Liverpool first existed as farmland within the West Derby Hundred before growing into a small town of farmers, fishermen and tradesmen and tactical army base for King John of England. A tidal creek, known as the Pool provided a natural harbour for ships. The town was planned with its own castle, although due to outbreaks of disease and its subordinance to the nearby Roman port of Chester, the town's growth and prosperity stagnated until the late 17th and early 18th centuries. There was substantial growth in the mid- to late 18th century, when the town became the European port most heavily involved in the Atlantic slave trade.

King John's letters patent of 1207 announced the foundation of the borough of Liverpool (then spelt as Liuerpul). There is no evidence that the place had previously been a centre of any trade. The borough was probably created because King John decided that it would be a convenient place to embark men and supplies for his Irish campaigns: in particular his Irish campaign of 1209. The original street plan of Liverpool is said to have been designed by King John near the same time it was granted a royal charter, making it a borough. The original seven streets were laid out in the shape of a double cross: Bank Street (now Water Street), Castle Street, Chapel Street, Dale Street, Juggler Street (now High Street), Moor Street (now Tithebarn Street) and Whiteacre Street (now Old Hall Street). Liverpool Castle was built before 1235, and survived until it was demolished in the 1720s. By the middle of the 16th century, the population was still around 600, although this was likely to have fallen from an earlier peak of 1,000 people due to slow trade and the effects of the plague.

In the 17th century, there was slow progress in trade and population growth. Battles for control of the town were waged during the English Civil War, including a brief siege in 1644. In 1699, the same year as its first recorded slave ship, Liverpool Merchant, set sail for Africa, Liverpool was made a parish by Act of Parliament. But arguably, the legislation of 1695 that reformed the Liverpool council was of more significance to its subsequent development. Since Roman times nearby Chester on the River Dee had been the region's principal port on the Irish Sea. However, as the Dee began to silt up, maritime trade from Chester became increasingly difficult and shifted towards Liverpool on the neighbouring River Mersey. The first of the Liverpool docks was constructed in 1715, and the system of docks gradually grew into a large interconnected system.