内陸国

Countries have acted to overcome being landlocked by acquiring land that reaches the sea:

• The Republic of Ragusa, in 1699, gave the town of Neum to the Ottoman Empire because it did not want to have a land border with the Republic of Venice.^[13] This small municipality was inherited by Bosnia and Herzegovina and now provides limited sea access, splitting the Croatian part of the Adriatic coast in two. Since Bosnia and Herzegovina is a new country, railways and ports have not been built for its need. There is no freight port along its short coastline at Neum, making it effectively landlocked, although there are plans to change this. Instead, the Port of Ploče in Croatia is used.
• The International Congo Society, which owned the territory now constituting the Democratic Republic of the Congo, was awarded a narrow piece of land cutting through Angola to connect it to the sea by the Conference of Berlin in 1885.
• After World War I, in the Treaty of Versailles, a part of Germany designated "the Polish corridor" was given to the new Second Polish Republic, for access to the Baltic Sea. This gave Poland a short coastline, but without a large harbour. This was also the pretext for making Danzig (now Gdańsk) with its harbour the Free City of Danzig, to which Poland was given free access. However, the Germans placed obstacles to this free access, especially when it came to military materiel. In response, the small fishing harbour of Gdynia was soon greatly enlarged.
• As a result of a 2005 territorial exchange with Ukraine, Moldova received a 600-metre (650-yard) long bank of the Danube (which is an international waterway),^[14] subsequently building its Port of Giurgiulești there.

Countries can establish agreements to provide for free transport of goods through neighbouring countries:

• The Treaty of Versailles required Germany to offer Czechoslovakia a lease for 99 years of parts of the ports in Hamburg and Stettin, allowing Czechoslovakia sea trade via the Elbe and Oder rivers. Stettin was annexed^[15] by Poland after World War II, but Hamburg continued the contract so that part of the port (now called Moldauhafen) until 2028^[16] could be used for sea trade by a successor of Czechoslovakia, the Czech Republic.
• The Danube is an international waterway, and thus landlocked Austria, Hungary, Moldova, Serbia and Slovakia have secure access to the Black Sea. However, oceangoing ships cannot use the Danube, so cargo must be transloaded anyway, and many overseas imports into Austria and Hungary use land transport from Atlantic and Mediterranean ports. A similar situation exists for the Rhine river where Switzerland has boat access, but not oceangoing ships. Luxembourg has such through the Moselle, but Liechtenstein has no boat access, even though it is located along the Rhine, as the Rhine is not navigable that far upstream.
• The Mekong is an international waterway so that landlocked Laos has access to the South China Sea (since Laos became independent from French Indochina). However, it is not navigable above the Khone Phapheng Falls.
• Free ports allow transshipment to short-distance ships or river vessels.
• The TIR Convention allows sealed road transport without customs checks and charges, mostly in Europe.^[17]

Losing access to the sea is generally a great loss to a nation, politically, militarily, and economically. The following are examples of countries becoming landlocked.

• The independence of Eritrea, brought about by the 30-year Eritrean War of Independence,^[18] caused Ethiopia to become landlocked. The Ethiopian Navy operated from foreign ports in Djibouti and Yemen before being dissolved in 1996, although it was later re-established as a brown-water navy in 2019.
• Montenegro's decision to abandon the State Union of Serbia and Montenegro caused the federal unit of Serbia to become a landlocked independent state.
• Bolivia lost its coastline to Chile in the War of the Pacific and accepted it in treaties signed in 1884 and 1904. The last treaty gives port storage facilities and special treatment for the transit of goods from and to Bolivia through Chilean ports and territory. Peru and Argentina have also given special treatment for the transit of goods. A fluvial Bolivian Navy, which did not exist at the time of the War of the Pacific, was created later and both trains and operates in Lake Titicaca and rivers. The Bolivian people annually celebrate a patriotic "Dia del Mar" (Day of the Sea) to remember its territorial loss, which included both the coastal city of Antofagasta and what has proven to be one of the most significant and lucrative copper deposits in the world. Early in the 21st century, the selection of the route of gas pipes from Bolivia to the sea fueled popular uprisings, as people were against the option of laying the pipes through Chilean territory.
• Austria and Hungary also lost their access to the sea as a consequence of the Treaty of Saint-Germain-en-Laye (1919) and the Treaty of Trianon (1920) respectively. Previously, although Croatia had a limited constitutional autonomy within the Kingdom of Hungary, the City of Fiume/Rijeka on the Croatian coast was governed directly from Budapest by an appointed governor as a corpus separatum, to provide Hungary with its only international port in the periods 1779–1813, 1822–1848 and 1868–1918. The most important ports in Austria were Trieste and Pula, now in Italy and Croatia.
• In 1801, the Nizam's dominion of Hyderabad State assumed its current borders as a landlocked princely state with territories in central Deccan, bounded on all sides by British India. For the preceding 150 years it had had a considerable coastline on the Bay of Bengal that was annexed by the British.^[19]
• It is possible that one of the causes of the Paraguayan War was Paraguay's lack of direct ocean access (although this is disputed; see the linked article).
• When the Entente Powers divided the former Ottoman Empire under the Treaty of Sèvres at the close of World War I, Armenia was promised part of the Trebizond vilayet (roughly corresponding to the modern Trabzon and Rize provinces in Turkey). This would have given Armenia access to the Black Sea. However, the Sèvres treaty collapsed with the Turkish War of Independence and was superseded by the Treaty of Lausanne (1923), which firmly established Turkish rule over the area.
• In 2011, South Sudan broke off from Sudan. As part of Sudan, South Sudan was landlocked, and this remained the case upon independence. There still remains conflict over the oil fields in South Sudan between the two countries.^[20]

The United Nations Convention on the Law of the Sea now gives a landlocked country a right of access to and from the sea without taxation of traffic through transit states. The United Nations has a programme of action to assist landlocked developing countries,^[21] and the current responsible Undersecretary-General is Anwarul Karim Chowdhury.

Some countries have a long coastline, but much of it may not be readily usable for trade and commerce. For instance, in its early history, Russia's only ports were on the Arctic Ocean and frozen shut for much of the year. The wish to gain control of a warm-water port was a major motivator of Russian expansion towards the Baltic Sea, Black Sea, and Pacific Ocean. On the other hand, some landlocked countries can have access to the ocean along wide navigable rivers. For instance, Paraguay (and Bolivia to a lesser extent) have access to the ocean through the Paraguay and Paraná rivers.

Several countries have coastlines on landlocked bodies of water, such as the Caspian Sea and the Dead Sea. Since these seas are in effect lakes without access to wider seaborne trade, countries such as Kazakhstan are still considered landlocked. Although the Caspian Sea is connected to the Black Sea via the man-made Volga–Don Canal, large oceangoing ships are unable to traverse it.

Some countries or important parts of countries have coastlines or river ports reachable by oceangoing ships, but only through a strait or river part of the territory of another country. The other country can put restriction on passage. Between 1429 and 1857 Poland, Sweden, Russia and other Baltic countries were subjected to the Sound Dues, a toll needed to be paid to reach Western European waters. Sweden bypassed it by conquering Scania in 1658.

The landlocked nature of a country can also hinder its ability to enforce international treaties. For example, Mongolia did not enforce an International Criminal Court arrest warrant issued at Vladimir Putin during his state visit, despite its obligation to do so as an International Criminal Court state party; Mongolia is landlocked and only borders Russia and China (both of whom are not ICC parties and are important economic partners with the country), which would make the delivery of Putin to the ICC headquarters in The Hague after his hypothetical arrest extremely difficult.^[22][23]

Three countries are landlocked by a single country (enclaved countries):

• Lesotho, a state surrounded by South Africa.
• San Marino, a state surrounded by Italy.
• Vatican City, a city-state surrounded by Italy, specifically Rome.

Seven landlocked countries are surrounded by only two mutually bordering neighbours (semi-enclaved countries):

• Andorra (between France and Spain)
• Bhutan (between China and India)
• Eswatini (between Mozambique and South Africa)
• Liechtenstein (between Austria and Switzerland) – one of the only two "doubly landlocked countries" in the world
• Moldova (between Romania and Ukraine) – ignoring Transnistria, a de facto state
• Mongolia (between China and Russia)
• Nepal (between China and India)

To this group could be added three landlocked territories, two of them de factostates with limited or no international recognition:

• Transnistria (between Moldova and Ukraine) – de facto state
• South Ossetia (between Georgia and Russia) – de facto state
• West Bank (between Israel and Jordan) – Israeli-occupied territory partly administered by the State of Palestine^{[24][25][26][27]}

A country is "doubly landlocked" or "double-landlocked" when it is surrounded entirely by landlocked countries (i.e. requiring the crossing of at least two national borders to reach a coastline).^[28][29] There are two such countries:

• Liechtenstein in Western Europe, surrounded by Austria and Switzerland.^[30]
• Uzbekistan in Central Asia, surrounded by Afghanistan, Kazakhstan, Kyrgyzstan, Tajikistan, and Turkmenistan.^[31]

神聖ローマ帝国の解体後、ヴュルテンベルク王国は、バイエルン、バーデン、スイス、ヘッセン大公国（ヴィンプフェン飛び地）、ホーエンツォレルン＝ジグマリンゲン、ホーエンツォレルン＝ヘヒンゲンと国境を接する二重内陸国となった。後者の2つは、互いに、ヴュルテンベルク、バーデンの間に挟まれた内陸国であった。1866年にプロイセンの飛び地となり、ヴュルテンベルクは沿岸国と国境を接するようになったが、海岸に出るには少なくとも2つの国境を越える必要があった。 1815年から1866年まで独立していたフランクフルト自由市は、ヘッセン選帝侯国、ヘッセン大公国、ヘッセン＝ホンブルク、ナッサウと国境を接していたため、二重内陸国であった。ドイツ連邦には、内陸国や沿岸国の飛び地としか国境を接していない内陸国が他にもいくつかあった。ヘッセン大公国、ヘッセン＝ホンブルク、ナッサウ（いずれも1866年まで）、ザクセン＝コーブルク＝ザールフェルト、ザクセン＝ヒルトブルクハウゼン（いずれも1826年まで）、ロイス（長男系）（1871年まで）である。これらはすべてプロイセンと国境を接していたが、海に面した主要領土とは接していなかった。

1871年のドイツ統一から第一次世界大戦終結まで、内陸国は存在しなかった。リヒテンシュタインはアドリア海に面したオーストリア＝ハンガリー帝国と国境を接しており、ウズベキスタンは当時、大西洋と海の両方に面したロシア帝国の一部であった。

1918年のオーストリア＝ハンガリー帝国の解体と、内陸国である独立オーストリアの成立に伴い、リヒテンシュタインは1938年まで唯一の二重内陸国となった。同年、オーストリアはナチス・ドイツに併合され、バルト海と北海に面する領土を獲得した。第二次世界大戦後、オーストリアは独立を回復し、リヒテンシュタインは再び二重内陸国となった。

かつてロシア帝国、そしてソビエト連邦の一部であったウズベキスタンは、1991年のソビエト連邦の崩壊に伴い独立を果たし、二度目の二重内陸国となった。

However, Uzbekistan's doubly landlocked status depends on whether the Caspian Sea is considered a lake or a sea. In the latter case, Uzbekistan is not doubly landlocked, since its neighbors Turkmenistan and Kazakhstan have access to the Caspian Sea.^[32]

内陸国と事実上の国家は、以下のように隣接するグループに分類できます。 ^{[ 33 ]}

• 東アフリカ、中央アフリカ、西アフリカのクラスター（10）：ブルキナファソ、ブルンジ、中央アフリカ共和国、チャド、エチオピア、マリ、ニジェール、ルワンダ、南スーダン、ウガンダ^{[ 34 ]}
• 東欧、南欧、西欧のクラスター（9）：オーストリア、チェコ、ハンガリー、コソボ、リヒテンシュタイン、北マケドニア、セルビア、スロバキア、スイス^{[ 35 ]}
• 中央アジアおよび南アジアクラスター（6）：アフガニスタン、カザフスタン、キルギスタン、タジキスタン、トルクメニスタン、ウズベキスタン^{[ 36 ]}
• 東部および南部アフリカのクラスター（4）：ボツワナ、マラウイ、ザンビア、ジンバブエ^{[ 34 ]}
• 東ヨーロッパグループ (2):モルドバおよび沿ドニエストル共和国(事実上の国家) ^{[ 35 ]}
• 南米グループ（2）：ボリビアとパラグアイ^{[ 37 ]}
• 西アジアグループ（2）：アルメニアとアゼルバイジャン^{[ 36 ]}

国連は、後発開発途上国、内陸開発途上国、小島嶼開発途上国向けの作業プログラムを実施するための専門作業グループ^{[ 38 ]を設立した[ 39 ] 。}

注記:

1. モアンダの40km （25マイル）の海岸線がなければ、コンゴ民主共和国はアフリカの2つのクラスターを1つにまとめ、世界最大の連続したクラスターとなるだろう。  
2. 中央アジア・南アジア地域と西アジア地域は、内陸のカスピ海によって繋がっており、ほぼ連続していると言える。モンゴルもほぼこの地域の一部であり、中国またはロシア領を挟んでカザフスタンからわずか30km （19マイル）しか離れていない。  
3. インドによるシッキム併合以前は、ヒマラヤ山脈に位置するブータン、ネパール、シッキムの3カ国は、独自の南アジアグループを形成していた。

内陸国の中で、他の内陸国と国境を接していない国は以下の12カ国です。

• アジア（4）：ブータン、ラオス、モンゴル、ネパール^{[ 36 ]}
• ヨーロッパ（6）：アンドラ、ベラルーシ、ルクセンブルク、モルドバ、サンマリノ、バチカン市国（聖座）^{[ 35 ]}
• アフリカ (2):エスワティニとレソト^{[ 34 ]}