The name Cumber comes from the Irish, com, together, and boir, water, so the name suggests the meeting place of two waters, the Rivers Glenradle and Faughan, in the vicinity of the village of Claudy, some thirteen kilometres east of Londonderry, just to the south of the main Belfast road. According to tradition, St. Patrick founded a church in the area. In 1622, the church was ruinous. It was in reasonable condition by 1693, and was rebuilt in 1757. The parish was divided into Cumber Upper and Lower in 1798.
Cumber Upper Church at Alla, two kilometres south of Claudy, was built in 1860. It is a three bay hall with a north aisle. The lean-to and gabled porch is in the south wall, and the tower is in the corner of the south and west walls. The copper spire was erected in 1960. Inside the porch there are stairs into the gallery, below which are the vestry rooms. These rooms, as well as the public address system and the rose window in the west wall, were donated by the Robinson family in memory of John and Annabella Robinson, 1995. There is another vestry room at the east end of the aisle. In the porch, the window commemorates Robert McFaul, a constable in the Royal Ulster Constabulary who died in 1984, and there is a plaque in memory of George and Jane McFaul.
There is a window of three lights and diamond glass in the west wall, with a rose window above. The first window illustrates Christ, the Light of the World, standing at the door and knocking, and is in memory of Samuel and Eileen Eakin, 1991. The second window has diamond opaque glass, with an inset illustrating the text, "and a little child shall lead them". It commemorates Kathryn Alexandra Eakin, ages eight years, who was killed in a bomb blast in Claudy in 1972. The window in the west ailse wall came from St. Nicholas' Church, Castlerickard in the Diocese of Meath, which was closed. It illustrates the text, "It is I, be not afraid", in memory of Richard Vernon Kellet. It was installed in the church in memory of James Whiteside, James McFaul, and Samuel Craig, 1979.
The baptistry is in the north aisle. The window in it shows Jesus welcoming the little children, and it is in memory of Paul Robinson, aged two years, 1964. The middle window in the aisle shows the raising of Lazerus, and it is in memory of John Robinson who died in 1964. The third window was installed in 1994, it shows on the left the text, "peace, be still", in memory of Joseph and Annie Haire, and on the right, Jesus giving a blessing, in memory of Annie Bonner who died in 1971.
There are three window in the sanctuary, which has three sides. The first window has, Ave Maria, gratia plena, Hail Mary full of Grace, the second has, Ego sum Pastor Bonus, I am the Good Shepherd, and the third has, et Verbum caro factum est, and the Word became flesh. The windows are in memory of Mary, wife of Charles Robinson, and daughter of Canon John Beckett, Rector 1905-1943.
The altar, the reredos and credence table were presented by Claude Braddel in memory of his wife Eileen, 1959. In the chancel, the prayer desk on the right was given in memory of Robert and Jayne Forsythe, 1959, and the prayer desk on the left, in memory of Edith Leslie, 1990. The pulpit on the left of the nave was erected by Ernest Browne and Constance Browne in memory of the Browne Family of Cumber House, 1938. There is a brass eagle lectern. A new organ was installed in the aisle, 1999. The detached console of two manuals and pedals is to the right of the nave.
A brass monument on the south wall commemorates Flight Sgt William Harkness, RAF, who was killed in 1943, and a memorial records the life of the Rev. Thomas Lindesay, Prebendary of Cumber, 1847-1860. On the north aisle wall, there is a memorial to Canon John Beckett who died in 1949, and to his wife Violet who died in 1942. It was presented by their daughter, Dorothea Harvey in the church's centenary year, 1960.