The last graduating class from Graham's School was in May 1908. The old school was located near the present Denmark Firemen's Hut. J. Arthur Wiggins, a local banker, was also serving as the superintendent of the Graham's school.
The town was migrating west nearer the center of the railroad activity and so the school would follow. A location on North Palmetto Avenue in Denmark was selected to build a new school. Approximately 4 1/2, acres with 351 feet frontage on North Palmetto Avenue was purchased from S. D. M. Guess August 28, 1907 by Denmark School District 21 for $2375. The new two story building housed grades one through ten, and the first classes entered for the school year 1908-09. E. A. Hall was the superintendent. The eleventh grade was added in 1911, and as the enrollment increased it became necessary to enlarge the size of the school house.
A new Denmark High School was built in 1920, and housed grades seven through eleven. The two buildings were joined by a covered walkway as the old auditorium and lunch room served both student bodies. E. T. Spigner was the first principal of the new high school. Hall and Spigner were followed by Superintendent A. J. Richards.
The addition of the twelfth grade in 1948 required even another extension of the front wing of the 1920 building. An additional acre with 220 feet frontage on North Palmetto Avenue had been purchased from Bethel Park Methodist Church, February 15, 1939 for $3500. The new front wing extension continued on this property adding five classrooms, a sick room, and a ladies teacher's lounge. Grades five and six were moved from grammar school to the back wing of the high school building.
Superintendents L. J. Hendrix and MC Hyatt and Principal Clarence Butts were succeeded by K. C. Hanna who initiated a phase of tremendous change in the school organization and plant. Under Hanna's administration Denmark Schools and Olar Schools were consolidated in 1957 and moved into a new high school building on South Palmetto Avenue.
The 1909 building was demolished, but the 1920 Denmark High School building continued to be used for elementary grades until 1987. The building has been abandoned since that time with no maintenance.