Cynthiana is a home rule-class city in Harrison County, Kentucky, in the United States. The population was 6,402 at the 2010 census. It is the seat of its county.
Cynthiana was named after Cynthia and Anna Harrison, daughters of Robert Harrison, who had donated land for its establishment, though Harrison County was named after Colonel Benjamin Harrison, who was an early settler in the area and the sheriff of Bourbon County.
Two Civil War battles were fought in Cynthiana; the first on July 17, 1862, was part of a raid into Kentucky by Confederate General John Hunt Morgan; the second on June 11 and 12, 1864, resulted in defeat of Confederate forces on Morgan's last raid into the state.
On January 23, 1877, an LL chondrite meteorite fell in Cynthiana.
March 2, 1997, the South Fork of the Licking River which bisects Cynthiana flooded, causing extensive damage in Cynthiana and neighboring communities.
In March, 2020, Cynthiana had the first case of COVID-19 in Kentucky.
Cynthiana is located in southern Harrison County at 38°23′18″N 84°17′49″W (38.388292, -84.296841). U.S. Routes 27 and 62 pass through the city, passing west of the downtown area. US 27 leads north 56 miles (90 km) to Cincinnati and south 14 miles (23 km) to Paris, while US 62 leads northeast 46 miles (74 km) to Maysville and southwest 21 miles (34 km) to Georgetown. Lexington is 31 miles (50 km) to the southwest via US 27 or 29 miles (47 km) via Kentucky Route 353.
According to the United States Census Bureau, the city has a total area of 4.1 square miles (10.5 km2), of which 4.0 square miles (10.4 km2) are land and 0.04 square miles (0.1 km2), or 1.09%, are water. The South Fork of the Licking River, a tributary of the Ohio River, flows south to north through the city, passing west of the downtown area.
The climate in this area is characterized by hot, humid summers and generally mild to cool winters.