Hamilton (Scots: Hamiltoun; Scottish Gaelic: Baile Hamaltan [ˈpalə ˈhaməl̪ˠt̪ʰan]) is a large town in South Lanarkshire, Scotland. It serves as the main administrative centre of the South Lanarkshire council area. It sits 10 miles (16 km) south-east of Glasgow, 37 miles (60 km) south-west of Edinburgh and 74 miles (120 km) north of Carlisle. It is situated on the south bank of the River Clyde at its confluence with the Avon Water. Hamilton is the county town of the historic county of Lanarkshire and is the location of the headquarters of the modern local authority of South Lanarkshire.

The town itself has a population of around 55,000, which makes it the 9th largest locality in Scotland, and anchors a defined settlement of 84,000 (including neighbouring Blantyre, Bothwell and Uddingston) which is the country's 8th largest.

The town of Hamilton was originally known as Cadzow or Cadyou (Middle Scots: Cadȝow), the "ȝ" being the letter yogh), pronounced /kadju/. It is an ancient settlement, possibly dating back to the days of Strathclyde, or perhaps earlier. The Roman fort of Bothwellhaugh lies nearby. A lost medieval settlement was excavated in the 2010s near the Clyde, only around 1 mile from the current town. It is known that kings of Strathclyde did have a hunting lodge near Cadzow, and the area may have been a royal centre during the later stages of the kingdom, as a precursor to Cadzow Castle.

During the Wars of Scottish Independence the Hamilton family initially supported the English and Walter fitz Gilbert (the head of the Hamilton family) was governor of Bothwell Castle on behalf of the English. However, he later changed loyalty to Robert the Bruce, following the Battle of Bannockburn, and ceded Bothwell to him. For this act, he was rewarded with a portion of land which had been forfeited by the Comyns at Dalserf and later the Barony and lands of Cadzow, which in time would become the town of Hamilton.

Cadzow was renamed Hamilton in the time of James, Lord Hamilton, who was married to Princess Mary, the daughter of King James II. The Hamilton family themselves most likely took their name from the lands of Humbleton or Homildon in Northumberland, or perhaps from a place near Leicester.

The Hamiltons constructed many landmark buildings in the area including the Hamilton Mausoleum in Strathclyde Park, which has one of the longest reverb times of any manmade building at 15 seconds. The Hamilton family are major land-owners in the area to this day. Hamilton Palace was the seat of the Dukes of Hamilton until the early-twentieth century.

Other historic buildings in the area include Hamilton Old Parish Church, a Georgian era building completed in 1734 and the only church to have been built by William Adam. The graveyard of the old parish church contains some Covenanter remains. Hamilton Townhouse, which now houses a library and concert hall, underwent a sympathetic modernization in 2002 and opened to the public in summer 2004. The ruins of Cadzow Castle also lie in Chatelherault Country Park, 2 miles (3 km) from the town centre.

Hamilton Palace was the largest non-royal residence in the Western world, located in the north-east of the town. A former seat of the Dukes of Hamilton, it was built in 1695, subsequently much enlarged, and demolished in 1921 due to ground subsidence. It is widely acknowledged as having been one of the grandest houses in Scotland, was visited and admired by Queen Victoria, and was written about by Daniel Defoe.