Frankfort is the capital city of the U.S. state of Kentucky. It is a home rule-class city and the seat of Franklin County. As of the 2020 census, the population was 28,602, making it the 13th largest city in Kentucky and 4th smallest U.S. state capital by population. Located along the Kentucky River in the Upland South, Frankfort is the principal city of the Frankfort, Kentucky micropolitan area, which includes all of Franklin and Anderson counties.

Before Frankfort was founded, the site was a ford across the Kentucky River, along one of the great buffalo trails used as highways in colonial America. English explorers first visited the area in the 1750s. The site evidently received its name after an incident in 1780, when pioneer Stephen Frank was killed in a skirmish with Native Americans; the crossing was named "Frank's Ford" in his memory. In 1786, the Virginia legislature designated 100 acres (40 hectares) as the town of Frankfort and, after Kentucky became a state in 1792, it was chosen as capital.

The city is located in the inner Bluegrass region of Kentucky. The Kentucky River flows through the city, making a turn as it passes through the center of town; the Downtown and South Frankfort districts are opposite one another on each side of the river. The suburban areas on either side of the river valley are known as East and West Frankfort. Frankfort has four distinct seasons; winter is normally cool with some snowfall, while summers are hot and humid.

Because of the city's location on the Kentucky River, it has flooded many times, with the two highest recorded floods occurring in 1937 and 1978. The North Frankfort levee, finished in 1969, and the South Frankfort floodwall, built in the 1990s, were constructed for flood protection. Five bridges cross the river in downtown Frankfort, including the St. Clair Street bridge and Capitol Avenue bridge. Notable locations include the Kentucky State Capitol building, the Capital City Museum, and Fort Hill, a promontory with a view of downtown.

As of 2016, the city's largest industry was public administration with 28% of the workforce. Manufacturing totaled over 12% of the workforce. Frankfort is adjacent to Interstate 64, and Interstate 75 is nearby; general aviation access is via the Capital City Airport, and commercial air travel is available through Blue Grass Airport in Lexington.

The town of Frankfort likely received its name from an event that took place in the 1780s. Native Americans attacked a group of early European colonists from Bryan Station, who were on their way to make salt at Mann's Lick in Jefferson County. Pioneer Stephen Frank was killed at the Kentucky River and the settlers thereafter called the crossing "Frank's Ford". This name was later elided to Frankfort.

In 1786, James Wilkinson purchased a 260-acre (110-hectare) tract of land on the north side of the Kentucky River, which developed as downtown Frankfort. He was an early promoter of Frankfort as the state capital. Wilkinson felt Frankfort would be a center of transportation using the Kentucky River to ship farm produce to the Ohio River and then to the Mississippi and on to New Orleans.

After Kentucky became the 15th state in 1792, five commissioners from various counties were appointed, on June 20, 1792, to choose a location for the capital. They were John Allen and John Edwards (both from Bourbon County), Henry Lee (from Mason), Thomas Kennedy (from Madison), and Robert Todd (from Fayette). A number of communities competed for this honor, but Frankfort won. According to early histories, the offer of Andrew Holmes' log house as capitol for seven years, a number of town lots, £50 worth of locks and hinges, 10 boxes of glass, 1,500 pounds (680 kg) of nails, and $3,000 in gold helped the decision go to Frankfort.