Sea of Marmara

"Propontis" redirects here. For the Liberian cargo ship, see SS Propontis.

Sea of Marmara
Marmara Denizi (Turkish)
The Bosphorus highlighted in red, the Dardanelles strait in yellow.
Sea of Marmara Location of the Sea of Marmara within Turkey
Bathymetry and surrounding relief
Location	Southern Europe and West Asia
Coordinates	40°40′N 28°00′E
Type	Inland sea
Primary inflows	Simav River, Biga Çayı, Nilüfer River
Primary outflows	Turkish Straits
Catchment area	11,500 km2 (4,400 sq mi)
Basin countries	Turkey
Surface area	11,350 km2 (4,380 sq mi)
Average depth	494 m (1,621 ft)
Max. depth	1,370 m (4,490 ft)
Water volume	3,378 km3 (810 cu mi)
Islands	Avşa, Ekinlik, İmralı, Marmara, Paşalimanı, and the Prince Islands
Settlements	Balıkesir, Bursa, Çanakkale, Istanbul, İzmit, Tekirdağ, and Yalova

Satellite image of the Sea of Marmara

Algal bloom on the Sea of Marmara

Satellite image showing metropolitan İzmit along northern and eastern shores

The Sea of Marmara, also known as the Sea of Marmora, the Marmara Sea, or Propontis (/prəˈpɒntɪs/; ancient Greek: Προποντίς /pro.ponˈdis/), is a small inland sea entirely within the borders of Turkey. It links the Black Sea and the Aegean Sea via the Bosporus and Dardanelles straits, separating Turkey's European and Asian sides. It has an area of 11,350 km² (4,380 sq mi), and its dimensions are roughly 280 km × 80 km (174 mi × 50 mi), considered as the smallest sea in the world. Its greatest depth is 1,370 m (4,490 ft).