London
- County:
- Madison County
- County Seat:
- Yes
- Area (mi²):
- 8.397
- State:
- Ohio
London is a city located in Madison County, Ohio. London has a 2026 population of 10,743. It is also the county seat of Madison County. London is currently growing at a rate of 1.83% annually and its population has increased by 4.61% since the most recent census, which recorded a population of 10,270 in 2020.