Rabbi Yechia Lahlou is buried in Ksar es-Souk, today Errachidia, near the Tafilalet at the foot of the Atlas peaks. His grave lies in the town's second Jewish cemetery, alongside those of two other locally venerated tzaddikim, Rabbi Moul Tria and Rabbi Moul Sedra.

Little is known of his life, and traditions differ about his era. According to Hevrat Pinto, he came from the Land of Israel as an emissary to Morocco about four hundred years ago and settled in Ksar es-Souk. There he taught Torah and ethics to children, trained teachers and shochatim, and devoted himself to improving the material and spiritual lives of the Jews of the region. Another tradition, reported in the Moroccan press, has him arriving in Morocco as early as the destruction of the First Temple, and it is not known why he settled in that place.

His fame as a great tzaddik and benefactor spread, and his home drew crowds: when a resident fell ill, the first thing he did was ask for Rabbi Yechia's prayers, convinced they would hasten his recovery. According to Hevrat Pinto, he passed away on Purim and was buried where he had lived; since then the Jews of Morocco celebrate his hilloula on Shushan Purim.

A local tradition tells that the Jews built a structure over his tomb, but it was found destroyed the next day, and again after it had been rebuilt and guarded; they understood that the tzaddik did not want a building over his grave but was glad to receive pilgrims. According to this account, the pilgrimage to his tomb began from that time.