From Ohio History Central
London is the county seat of Madison County, Ohio. Patrick McLene established the community in 1810 or 1811, on land owned by John Murfin. It is unclear why residents named the town London. Many people believe that residents, many of whom were from Great Britain, named the town after London, England. Other people speculate that residents named the community after the London Company, which surveyed the land.
London grew slowly, having only 297 residents in 1840. By 1846, London only contained two churches, a private school, eight stores, and one newspaper office. Over the next several decades, London�s population grew dramatically. This growth was partly due to the completion of two railroads that passed through the town. By the late 1850s, London became a center of livestock auctions, attracting people from across the United States. In 1880, 3,067 people resided in London, with approximately one-third of these people being school-aged children. The number of town residents increased to 3,292 people by 1890. In 1886, London contained four newspaper offices, seven churches, and two banks.
During the twentieth century, London continued to grow. With a population of 8,771 people, London was Madison County�s largest community in 2000. The main reason for this increase was the large number of residents from Columbus, in nearby Franklin County, who sought to escape that city�s busyness by moving to more rural, neighboring communities. Many Madison County residents actually work in Ohio�s capital city. Other London residents find employment at the London Correctional Facility, one of Ohio�s state prisons.