The lake is approximately 20 miles (32 km) long and varies in width, but is rarely more than one mile (1.6 km) wide; it covers approximately 8,500 acres (34 km2). It was named for David Blackshear, the founder of Fort Early. When the dam was constructed, little effort was made to cut the trees that would soon be underwater. It was believed that the trees would soon die and decompose once submerged. While this was true for many of the trees, there are still many living Cypress trees in the middle of the lake and there are still many dead trees that have not fallen down.