Clearwater is a city in and the county seat of Pinellas County, Florida, United States, west of Tampa and north of St. Petersburg. To the west of Clearwater lies the Gulf of Mexico and to the southeast lies Tampa Bay. As of the 2020 census, the city had a population of 117,292. It is the smallest of the three principal cities in the Tampa–St. Petersburg–Clearwater metropolitan area, most commonly referred to as the Tampa Bay area.

Clearwater Beach is part of the city of Clearwater, but is separated from it by the Intracoastal Waterway. Cleveland Street is one of the city's historic avenues, and the city includes BayCare Ballpark and Coachman Park.

The Church of Scientology owns the majority of property in the Clearwater downtown core district.

Present-day Clearwater was originally the home of the Tocobaga people. Around 1835, the United States Army began construction of Fort Harrison, named after William Henry Harrison, as an outpost during the Seminole Wars. The fort was located on a bluff overlooking Clearwater Harbor, which later became part of an early 20th-century residential development called Harbor Oaks. University of South Florida archaeologists excavated the site in 1962 after Mark Wyllie discovered an underground ammunition bunker while planting a tree in his yard.

The area's population grew after the Federal Armed Occupation Act of 1842 offered 160 acres (0.65 km²) to anyone who would bear arms and cultivate the land. Early settlers included the Stevens, Stevenson, Sever and McMullen families, who claimed and farmed large tracts of land. Prior to 1906, the area was known as Clear Water Harbor. The name "Clear Water" is thought to have come from a fresh water spring flowing from near where the old City Hall building was located. There were many other freshwater springs that dotted the bluff, many in the bay or harbor itself.

Originally part of Hillsborough County, the first road joining Clearwater and Tampa was built in 1849, which dramatically reduced the prior day-long commute between the cities.

During the American Civil War, Union gunboats repeatedly raided the community's supplies, as most of the able-bodied men were away fighting for the Confederate Army. The town began developing in the late nineteenth century, prompted by Peter Demens' completion of the first passenger railroad line into the city in 1888. Clearwater was incorporated in 1891, with James E. Crane becoming the first mayor. The area's popularity as a vacation destination grew after railroad magnate Henry B. Plant built a sprawling Victorian resort hotel named Belleview Biltmore just south of Clearwater in 1897.

By the early 1900s, Clearwater's population had grown to around 400, ballooning to nearly 1,000 in the winter. Clearwater's oldest existing newspaper, the Clearwater Sun, was first published on March 14, 1914 (and ran until 1989). Clearwater was reincorporated, this time as a city, on May 27, 1915, and was designated the county seat for Pinellas County, which broke from Hillsborough County in 1912. In 1915, a bridge was built across Clearwater Harbor, joining the city with Clearwater Beach to the west. Clearwater Beach, although located on a separate barrier island, belongs to the city of Clearwater and fronts the Gulf of Mexico. A new, much higher bridge now arcs over the bay, replacing the former drawbridge; the connecting road is part of State Road 60 and is called Clearwater Memorial Causeway.