Constructed in 1936, Dennis was the first high school for African Americans in Lee County, including Bishopville and nearby rural areas. In contrast with the much larger Bishopville High School, which was built for white students the same year, it was a prime example of the inequalities of South Carolina's "separate but equal" system. The school for whites cost $71,000 to build, while the black high school was constructed for only $17,500.
In 1954, during the era of Brown v. Board of Education, the state renovated Dennis High School in an effort to change the perception of discrimination against black students. Dennis closed when schools in Lee County were integrated in 1970.