International Law and Acquisition of Territory by State


Every State has territory over which it exercises unfettered control. A State cannot exist without a territory and an entity without a territory is but a State.

It is this fact that has seen the struggle to acquire territories by States over the centuries.

International law,on its part, has sort to regulate how States acquire territories mainly so as to protect smaller States and preserve international peace and security.

The regulations have varied over time. This article will focus on contemporary international law regulations on the acquisition of State territory.

The International Court of Justice (ICJ) in  Netherlands v US or  the Island of Palmas Case ((1928) 2 RIAA, 829) defined State territory as the part of the globe where a State exercises sovereignty to the exclusion of all other States.

This is demarcated by boundaries and consists of the landmass(which includes the landmass below the earth and the atmosphere up to the troposphere),

internal and territorial waters but does not include high seas and outer space even if located in a State’s territory as they are _res communis_ (belong to all States and not to be claimed by any State).


International law accepts the following methods:

1. OCCUPATION: Occupation here relates to a historical mode of acquiring territory and not military or illegal seizure.

A State may acquire territory by the occupation of that territory.

There are two conditions precedent to the acquisition of territory by occupation, as laid down by the Court in  the Eastern Greenland Case ((1933) No. 53).

They are:

(a) the animus i.e intention of the State to act as sovereign;

(b)adequate exercise or display of sovereignty over the territory. The display of sovereignty must be by the government and not private individuals, unless it is backed by official action.

See the Norwegian Fisheries Case ((1951) ICJ Rep, 116. Occupation by planting of flags on virgin or vacant territories merely confers inchoate title on the occupiers.

Variants of ownership by occupation is the:

  • continuity and
  • contiguity theories.

See Western Saharan Case ((1975) ICJ Rep. 12).

See also Umozurike, U. O., Introduction to International Law 3rd ed. (Spectrum Law Series, 2007), pp 68-70.

2.PRESCRIPTION: This is acquisition of territory arising from the long, peaceful, public and uninterrupted possession of a territory.

The length of time territory is held is not universal and is dependent on other contingent factors.

It suffice that the State exercises de facto sovereignty on the territory and its possession thereof is unchallenged nor adverse by/to another State.

3. CESSION: A State may transfer title to its territory to another by way of gift, lease, exchange, grant or sale.

When any of these is done, that other State acquires bona fide title to the territory insofar as sovereignty is also transferred.

For instance, England leased Hong Kong from China in 1899, Russia sold Alaska to the US in 1867,

Denmark sold Danish West Indies to the US in 1916, etc. Transfer of title must be by treaty and not orally.

4.ANNEXATION: This is the acquisition of territory by force, whether military or economic or even political.

Acquisition of territory was the order of the day in the heydays but modern international law forbids it.

A territory acquired by annexation is likely not to be recognised by the community of States.

This explains, for instance, the refusal of many States to recognise territories seized from Palestine by Israel.

Article 2(4) of the UN Charter forbids the use of force against the territorial sovereignty or political independence of another State.

Annexation could however confer title to territory where the territory is abandoned by previous sovereigns or is irretrievably subdued and incorporated into the territory of the annexing State.

An army attempting to recover an occupied territory cannot be said to be annexing that territory.

Territories may also be acquired, inter alia, by accretion , avulsion and boundaries.

See: Umozurike, op. cit, Brownlie, I: African Boundaries, A Legal and Diplomatic Encyclopedia, 1979.

Abraham Aigba the author of international law and territory

By Abraham O. Aigba,

LL.B (Hons)



Hi there, I am Jeremiah Michael from Edo state, Nigeria. Currently a law student in Ambrose Alli University. Blogging came as another way to showcase what I have to offer

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