Clearwater is a city located in Pinellas County, Florida, United States, nearly due west of Tampa and northwest of St. Petersburg. To the west of Clearwater lies the Gulf of Mexico and to the east lies Tampa Bay. As of the 2010 census, the city had a population of 107,685. It is the county seat of Pinellas County. Clearwater 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. 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 under ground 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 (0.65km2) to anyone who would bear arms and cultivate the land. Early settlers included the Stevens, Stevenson 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 City Hall building is located today. 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.