Tannaghmore is a Catholic maintained, co-educational, primary school with a long established record of service to education in North Lurgan. The first school house in Tannaghmore was erected in 1827 on Castor Bay Road. It became the first school in the north-east of Armagh to apply for connection with the National System of Education on the 29th of December 1833.
Due to the movement of population towards the town of Lurgan, the school moved to its present site in 1908 when the erection of a two room red brick building signalled the beginning of the present day school. An extension of the school was undertaken in 1936 by Charles Lavery and Sons, with the addition of two classrooms, two cloak-rooms, a linking corridor and detached toilet block.
A house building programme in the area in the 1940s soon led to the new cloakrooms and corridor being used as classrooms. Parents objected and in 1952 took their children out on strike. As a result Orlit Construction Company undertook a further extension in 1953 providing four additional classrooms, a dining/assembly hall, a new toilet/cloak-room block and a linking corridor.
Tannaghmore's continuing expansion throughout the 1960s necessitated extra accommodation. This was found in the nearby St. Colman's Hall, the headquaters of Clan Eireann Youth Club.
In 1969 the largest extension yet was completed on the north side of the school by the Dungannon building firm of Donnelly, Connelly and Fee. This comprised eighteen additional classrooms, an assembly/gym hall, a meals kitchen, two dining halls, adequate toilet/cloak facilities, linking staircases and corridors, tarmac and grass play areas. Yet even this building programme did not satisfy the demand for places and in the early 1970s two semi-permanent and four mobile classrooms were located in the back playground. All are still in use at this present time.
The most recently acquired accommodation, a mobile remedial unit funded under the "Improving Schools Initiative", was located on the site in the autumn term of 1996.