1. The Bobby Jackson mural of the Siege Of Derry and King William Crossing The Boyne dates back to the nineteen twenties or forties (sources disagree!). The mural was touched up annually and the wall itself was moved in the 1970s. The wall was eventually destroyed in 1995 and a new, similar, mural painted. This new mural is maintained by Bobby Jackson Jr, on boards and only on public display during marching season in the Fountain, Londonderry. (The Jackson murals have their own Visual History page.)
2. The King Billy in Rockland Street (in the Village) dates back to the nineteen thirties and survived until 1989 (at least). The (unattributed and undated) image below is perhaps of a version painted in 1969: (M00800)
For an 1984 image, see C00421.
3. Free Derry Corner was first painted in 1969 and has been in constant use since then, despite the house it was attached to being knocked down.
Both Free Derry Corner and the rear of Free Derry Corner (first painted in 1983) have their own Visual History pages.
Free Derry Corner in 1972. (M00075)
4. The top candidate for the longest-lasting mural without repainting is in Anne Street (now Brandywell Court) in Derry. It was painted in 1981 or 1982 and is in surprisingly good shape given that it has not been touched in ~35 years.
Google Maps link.
5. Also almost exactly in its original form – though repainted – is the phoenix in Clowney Street. It was first painted in 1981 and has been touched up in 1987 and 1990 and repainted in 2013. 1981