Final answer:
Greece has the Ionian Sea forming much of its western coast. This country is situated in Southern Europe on the Balkan Peninsula and is known for its numerous islands and rich cultural history.
Step-by-step explanation:
The country that has the Ionian Sea forming much of its western coast is Greece. Located in Southern Europe, Greece is part of the Balkan Peninsula and includes a myriad of islands, the largest being Crete. The Ionian Sea is an elongated embayment of the Mediterranean Sea, lying to the west of Greece and to the east of Italy and Albania.
Historically, Greece, along with other western-aligned countries, has played a significant role in the cultural and political evolutions of the region. Today, the Ionian Sea is not only vital for Greece's geography but also for its economy, as it aids in maritime trade and tourism.