Keystone Heights is a city in southwestern Clay County, Florida, with a small portion extending into Bradford County. It is the southwesternmost community in the Jacksonville metropolitan area and serves as the principal city and economic anchor of North Florida's Lake Region, an area spanning parts of Clay, Bradford, Putnam, and Alachua counties known for its many lakes. The 2020 census counted 1,446 residents. The city's origins lie in the Florida land boom of the 1920s. Keystone Heights was founded by settlers from Pennsylvania and other northern states who were drawn to the area's mild climate and abundant lakes for vacationing and year-round living. The surrounding seepage lakes — including Lake Geneva and Lake Brooklyn — recharge the Floridan aquifer through rainfall and have long defined the community's identity, supporting fishing, boating, and swimming that remain central to local life. Keystone Heights' economy and character are shaped by its setting and its neighbors. The nearby Camp Blanding, a large Florida National Guard training installation and wildlife management area, and Gold Head Branch State Park, one of Florida's earliest state parks, bring a mix of military families, outdoor recreation, and visitors to the area. The city itself functions as a small commercial and residential hub for the Lake Region, with a school-centered community and a history as a popular retirement destination. The city is served by Clay County Schools, with Keystone Heights Elementary School and Keystone Heights Junior/Senior High School anchoring the local system. State Road 100 runs through town, and the Palatka-to-Lake Butler State Trail, a rail-to-trail corridor, parallels the roadway, adding a recreational spine to the community. Keystone Heights suits retirees, families, and outdoor enthusiasts who want a quiet, affordable lake-country lifestyle in North Florida, with Gainesville and Jacksonville each about 40 minutes away. It appeals especially to those who value water access, a small-town pace, and proximity to the region's parks, trails, and military community.