Greenside Mine (sometimes referred to as Greenside Lead Mine) was a successful lead mine in the Lake District of England. Between 1825 and 1961 the mine produced 156,000 long tons (159,000 tonnes) of lead and 1,600,000 ounces (45 tonnes) of silver, from around 2 million tons of ore. During the 1940s it was the largest producer of lead ore in the UK. Unusually for a 19th-century metalliferous mine in Britain there are very full records of its activities, dating back to 1825.