The Svingerud Runestone is a sandstone object featuring Elder Futhark inscriptions found in a grave west of Oslo, Norway. Radiocarbon dating indicates that the grave and the runestone date to between 1 and 250 CE, during the Roman Iron Age, making it the oldest datable runestone known in the world,...
https://en.wikipedia.org/wiki/Svingerud_Runestone
The oldest I could find from Scotland is the Book of Deer written around 850ad