In the second half of the 7th century, the first Bulgarians to the north of the Danube Delta came and settled here. This clan was located in the Bulgarian Turkish colony, in the area between the river Dniehper and the Azov Sea, to the north of the Caspian Sea. By the end of the 6th century, these Bulgarian Turks' countries, which formed a union of groups with the same tradition and culture speaking the same language, would be called Great Bulgaria in the works of Byzantine history writers. Kubrat Khan was at the beginning of these clans. However, after his death, these units were dismantled. Therefore, some of these first Bulgarians came from the sons of Kubrat, led by Asparuh, to the Danube delta, to present-day Serbia. As a matter of fact, we tried to make an assessment on the historical geographical and ethnic structures of the Bulgarians in the Black Sea through the details mentioned above in this study.
Key words: First Bulgarians, Danube Delta, Dniepher River, Black Sea.