The preliminary report describes the first results of two field expeditions to the Al-Ghat governate of Saudi Arabia. Jan Tavernier and Elynn Gorris discovered and documented in the Wadi el-Markh more than 80 Old North Arabian petroglyphs. In the epigraphic chapter of the report, the two authors published the preliminary reading of about 25 inscriptions in various Old North Arabian dialects. The variety in Old North Arabian dialects at the site may indicate that the Wadi el-Markh was located at a strategic Transarabian commercial route