Louisville is the largest city in the U.S. state of Kentucky, and the county seat of Jefferson County. Since 2003, the city's borders have been coterminous with those of the county because of a city-county merger. Louisville is situated on the Ohio River in north-central Kentucky at the Falls of the Ohio. Louisville is today most well known for the Kentucky Derby, the widely watched first race of the Triple Crown of Thoroughbred Racing. Louisville has emerged as a major center for the health care and medical sciences industries. Louisville has been central to advancements in heart and hand surgery as well as cancer treatment. Louisville also prides itself in its large assortment of small, independent businesses and restaurants, some of which have become known for their ingenuity and creativity.