Spring Hill is a census-designated place (CDP) in Hernando County, Florida, in the United States of America. The community is unincorporated. The population was 113,568 at the 2020 census, up from 98,621 at the 2010 census. Spring Hill belongs to Florida's Nature Coast region and is in the Tampa-St. Petersburg-Clearwater metro area. It is east of Hernando Beach, southwest of Brooksville, and north of Tampa.

Spring Hill was formerly a large tract of endangered Longleaf Pine Ecosystem and Sand Pine Scrub with very high biodiversity, and it was a safe haven for many imperiled species. Most of that ecosystem remained unchanged until the 1970s when large scale deforestation for development began.^{[citation needed]} The community first appeared on Hernando County maps as early as 1856 along what is today Fort Dade Avenue just north of the community of Wiscon.

The modern Spring Hill was founded in 1967 as a planned community, which was developed by the Deltona Corporation and the Mackle Brothers. The developers originally wanted to call the community "Spring Lake" and used that as the working name throughout the development process. Eventually, they were forced to use a different name due to the name Spring Lake already being in use locally and they chose "Spring Hill". The plans for the community are identical to the community of Deltona. The Mackle Brothers sold many of the properties and land in the area through intense advertising on a national scale. The community has since become a sprawling semi-city in its own right, although it is an unincorporated area. The main entrance to the original development is marked by the Spring Hill waterfall on Spring Hill Drive and U.S. Route 19 (Commercial Way).

Spring Hill's proximity to Tampa, 40 miles (64 km) to the south, and the completion of the Suncoast Parkway in 2001 have made the community easily accessible to the Tampa-St. Petersburg area.

Spring Hill is located in southwestern Hernando County. It is bordered to the west by Timber Pines; to the north by Weeki Wachee, North Weeki Wachee, High Point, Brookridge, and Wiscon; and to the east by South Brooksville, Garden Grove, and Masaryktown. To the south it is bordered by Shady Hills and Heritage Pines in Pasco County.

According to the United States Census Bureau, Spring Hill has a total area of 62.2 square miles (161.2 km²), of which 59.8 square miles (154.9 km²) are land and 2.4 square miles (6.3 km²), or 3.94%, are water.

Postal mailing address names for this community are divided into "Shady Hills" and "Quail Ridge" for correct postal address coverage. The Spring Hill census designated place does not extend into neighboring Pasco County, so the U.S. Postal Service recommends that "Spring Hill" be used only as the mailing address for destinations in ZIP Code 34610 of Pasco County, not for postal customers in this Hernando County unincorporated community.

As of the 2020 census, Spring Hill had a population of 113,568, with 44,029 households and 30,380 families residing in the CDP.