Longboat Key is a town in Manatee and Sarasota counties along the central west coast of the U.S. state of Florida, located on and coterminous with the barrier island of the same name. Longboat Key is south of Anna Maria Island, between Sarasota Bay and the Gulf of Mexico. It is almost equally divided between Manatee and Sarasota counties. The town of Longboat Key was incorporated in 1955 and is part of the North Port-Bradenton-Sarasota, Florida Metropolitan Statistical Area. The town's population was 7,505 at the 2020 census, up from 6,888 at the 2010 census.

Longboat Key was originally inhabited by Native Americans. The area of what is now Longboat Key was scouted by Juan de Añasco, the first known European to explore the key and Hernando De Soto's as his scout. He spent about two months attempting to find a landing site, and he was also most likely the first European man to see and explore Sarasota Bay, Boca Ciega Bay and the Manatee River. According to local legend, he believed the Indians were hostile. When the party reached land on the island, the Indians fled leaving their Longboat in a bayou. Pirate Jean Lafitte was said to have been shipwrecked near or on Longboat Key.

Prior to 1842, Cuban and Spanish fishermen along with some squatters resided on the island. A fishing camp and a trading post for Native Americans existed in the northern part of the key located in what is presently the Longboat Village. At the time, the area was referred to on maps as "Saraxola" and "Zarazote". An 1839 map compiled by order of General Zachary Taylor during the Second Seminole War called the island Palm Island.

There is little known about the island between 1848 and the 1880s, since a hurricane hit the area and destroyed most of Longboat Key. The only thing known is that Charles Abbe had a plantation at an unknown location on the island where citrus and pineapples were grown.

The first people of European descent to claim land on the island were Colin and Rowlin W. Witt, claiming 7.15 acres (2.89 ha) on the north end of the island in 1882. Several others would claim land on the island during the late 1800s, but none of them are known to have lived on the island permanently.

In 1884, Thomas Mann claimed 144.5 acres (58 ha) on the key. He and his family moved there in 1888, becoming the first known permanent residents on the key. His home was located somewhere on the north end of the key.

Mann was a carpenter by trade who was originally from Indiana and later moved to Minnesota. During the American Civil War he served the Union under the 7th Minnesota Infantry Regiment. Mann and his family moved to what is known today as Bradenton in 1872. He left because of either a local yellow fever epidemic or prejudice against him from being from the Northern United States. Mann died in 1908 in nearby Cortez. His son, James, claimed 143.5 acres (58 ha) south of his father's land in 1891.

In 1895, with a passage being dug in from Sarasota Bay to Tampa Bay, steamships and paddle boats could access the island. Soon, a mail service was established that brought residents mail from Cortez. Thomas Mann sold his land in 1898 to May and June Pointevesant of Ocean Springs, Mississippi.