is a town in New London County, Connecticut, United States. The population was 7,406 at the 2000 census. It is a popular summer resort and artists' colony. Old Lyme and its neighboring town Lyme are the namesake for Lyme disease.
The US headquarters of Sennheiser is located in Old Lyme, as is Callaway Cars, the Florence Griswold Museum (including the Florence Griswold House), the Lyme Academy College of Fine Arts, and the Lyme Art Association.
The town of Old Lyme contains several villages, including Black Hall, Laysville, Lyme, Soundview, and South Lyme.
According to the United States Census Bureau, the town has a total area of 28.8 square miles (74.6 km²), of which, 23.1 square miles (59.8 km²) of it is land and 5.7 square miles (14.8 km²) of it (19.85%) is water.