This is a detailed list of performances by County Louth athletes in major international track & field championships. The list includes performances in global, continental and Commonwealth events at senior level both outdoors and indoors.

It includes athletes who were members of a Louth club at the time of the performance, as well as former members of Louth clubs/participants in the Community Games in Louth who would generally be regarded as being "originally from" County Louth or who were living in County Louth at the time of the performance, regardless of which country they were representing at the time.