The largest alluvial gold nugget in history, called the "Welcome Stranger", is found in Moliagul, Victoria, Australia.

Alluvium is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is typically geologically young and is not consolidated into solid rock. Sediments deposited underwater, in seas, estuaries, lakes, or ponds, are not described as alluvium. Floodplain alluvium can be highly fertile, and supported some of the earliest human civilizations.

Gold is a chemical element; it has chemical symbol Au and atomic number 79. In its pure form, it is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals. It is one of the least reactive chemical elements, being the second lowest in the reactivity series, with only platinum ranked as less reactive. Gold is solid under standard conditions.

Welcome Stranger is the name of the largest alluvial gold nugget ever discovered. It was unearthed by Cornish miners John Deason and Richard Oates on 5 February 1869 in Moliagul, 9 miles north-west of Dunolly in Victoria, Australia.

Moliagul is a locality in the Shire of Central Goldfields and Shire of Loddon, Victoria, Australia, located 202 kilometres (126 mi) northwest of Melbourne and 60 kilometres (37 mi) west of Bendigo. The area is notable for the discovery of a number of gold nuggets. These finds include the world's largest, the Welcome Stranger, which was discovered in 1869 by John Deason and Richard Oates. At the 2021 census, Moliagul had a population of 80.