page_title: Gulf of Finland
section_title: Geography
hierarchical_section_title: Gulf of Finland / Geography
caption_attribution_description: English: Gulf of Finland. Bounding box West 19.5°, South 58.8°, East 30.5°, North 61.0°. Center at 59°54′00″N 25°00′00″E﻿ / ﻿59.90000°N 25.00000°E. Русский: Финский залив. Suomi: Suomenlahti. Eesti: Soome laht. Svenska: Finska viken. Deutsch: Finnische Meerbusen.
context_page_description: The Gulf of Finland is the easternmost arm of the Baltic Sea. It extends between Finland and Estonia all the way to Saint Petersburg in Russia, where the river Neva drains into it. Other major cities around the gulf include Helsinki and Tallinn. The eastern parts of the Gulf of Finland belong to Russia, and some of Russia's most important oil harbours are located farthest in, near Saint Petersburg. As the seaway to Saint Petersburg, the Gulf of Finland has been and continues to be of considerable strategic importance to Russia. Some of the environmental problems affecting the Baltic Sea are at their most pronounced in the shallow gulf.
context_section_description: The gulf has an area of 30,000 km² (12,000 sq mi). The length (from the Hanko Peninsula to Saint Petersburg) is 400 km (250 mi) and the width varies from 70 km (43 mi) near the entrance to 130 km (81 mi) on the meridian of Moshchny Island; in the Neva Bay, it decreases to 12 km (7.5 mi). The gulf is relatively shallow, with the depth decreasing from the entrance to the gulf to the continent. The sharpest change occurs near Narva-Jõesuu, which is why this place is called the Narva wall. The average depth is 38 m (125 ft) with the maximum of 100 m (330 ft). The depth of the Neva Bay is less than 6 metres (20 ft); therefore, a channel was dug at the bottom for safe navigation. Because of the large influx of fresh water from rivers, especially from the Neva River (two-thirds of the total runoff), the gulf water has very low salinity – between 0.2 and 5.8 ‰ at the surface and 0.3–8.5 ‰ near the bottom. The average water temperature is close to 0 °C (32 °F) in winter; in summer, it is 15–17 °C (59–63 °F) at the surface and 2–3 °C (36–37 °F) at the bottom. Parts of the gulf can freeze from late November to late April; the freezing starts in the east and gradually proceeds to the west. Complete freezing usually occurs by late January, and it may not occur in mild winters.
  Frequent strong western winds cause waves, surges of water and floods.
  The northern coast of the gulf is high and winding, with abundant small bays and skerries, but only a few large bays (Vyborg) and peninsulas (Hanko and Porkkalanniemi). The coast is mostly sloping; there are abundant sandy dunes, with occasional pine trees. The southern shores are smooth and shallow, but along the entire coast runs a limestone escarpment, the Baltic Klint, with a height up to 55 m (180 ft). In the east, the gulf ends with Neva Bay; in the west it merges with the Baltic Sea.
  The gulf contains numerous banks, skerries and islands. The largest include Kotlin Island with the city of Kronstadt (population 42,800), Beryozovye Islands, Lisiy Island, Maly Vysotsky Island with the nearby city of Vysotsk (population 1706), Hogland (Suursaari), Moshtchny (Lavansaari), Bolshoy Tyuters (Tytärsaari), Sommers, Naissaar, Kimitoön, Kökar, Seskar (Seiskari),  Pakri Islands and others.
  Starting in 1700, Russia constructed nineteen artificial islands with fortresses in the gulf. They aimed to defend Russia from maritime attacks, especially in the context of the Great Northern War of 1700–1721. Such fortresses include Fort Alexander, Krasnaya Gorka, Ino, Totleben and Kronshlot.
  The largest rivers flowing into the gulf are the Neva (from the east), the Narva (from the south), and the Kymi (from the north). Keila, Pirita, Jägala, Kunda, Luga, Sista and Kovashi flow into the gulf from the south. From the north flow the Sestra River, Porvoo, Vantaa and several other small rivers. The Saimaa Canal connects the gulf with the Saimaa lake.
caption: Gulf of Finland
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