Greenside Mine was a successful lead mine in the Lake District of England. Between 1825 and 1961 the mine produced 156,000 long tons of lead and 1,600,000 ounces 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.