Built in 1889, the Northeastern State University Seminary Hall is the oldest building on campus. Northeastern State University was originally founded in 1851 as the Cherokee National Female Seminary. The original school was located in Park Hill, but was destroyed by a fire on Easter Sunday in 1887. Two years later, the school was rebuilt in Tahlequah, where it remains to this day.

Some believe that the NSU Seminary Hall is haunted. There have been strange reports of photographed orbs, puzzling sounds and odd smells. Others claim to have seen a female ghost wearing either a black uniform or white wedding gown. Some believe it is the ghost of Florence Wilson, a principal who spent 26 years at the Cherokee National Female Seminary. Wilson's fiancee, Pleasant Buchanan, was thought to have perished in the Civil War, and Wilson never married. Some believe she never left the school.

This historic building celebrated its 130th anniversary in 2019, and remains a spring board for education and new ideas.