1. 6.1 Territory
According to Oppenheim L.F.L 1955:451 State territory is the portion of surface of the globe which is subjected to the sovereignty of the state- land, air, sea, subsoil…
Territory therefore is a tangiable attribute of the state within which a state enjoys and excersises sovereignty.
Territories can be acquired or have been acquired by several means

2. 6.2 occupation
It is a means of acquiring a territory that is terra nullius.
Occupation is preceded by discovery, but discovery alone is not enough as there is need for the publication of the discovery followed by effective occupation i.e. the actual exercise of authority.
Effective occupation relates to the actual exercise of sovereignty. In areas that are inhabitable may be minimal- meaning minimum overt actions may be sufficient. Read Cllipperton Island Arbitration case, Island of Palmas Case.
Date of location of sovereignty is critical- the western Sahara case, El Salvador vs Honduras case.

3. 6.3 Prescription
Prescription is the acquisition of a territory by public, peaceful and continuous control of territory. It is different from occupation in that terra nullius is involved.
Length of time required is not stated as it is dependent on circumstances of each particular case, the geographical nature of the territory and the existence or absence of competing claims.

4. 6.4 Conquest
Is the taking of territory by force most often involving war.
Conquest under modern international law is no longer recognized. Attempts by Iraq over Kuwait led to resolution 660.
About territories acquired when it was lawful –doctrine of intertemporal law works- the law applicable when title was allegedly established.

5. 6.5 Cession
Means the transfer of territory by one sovereign to another normally done through a treaty-Versailles treaty 1919, Japan treaty of peace of 1951, cession of Hong Kong by China to Grat Britain after the opium war
It may also take the form of exchange (1890 Britain and German exchange Zanzibar and Heligoland).sale (Louisiana from France and Alaska from soviet union).
The emergence of self determination has made cession of territory between states less likely.

6. 6.6 Accretion and Avulsion
Through geographical processes. But these are rare in occurance and of minor importance.
Accretion involves gradual increase of territory through operation of nature e.g shift in river course Mississippi vs Louisiana
Avulsion through violent changes alteration of a river course of volcanic eruption.

7. 6.7 Self determination and Independence
The attainment of independence with the principle of self determination involves the replacement of a territory by another hence gives title to the territory.
An entity that comes through unconstitutional means survival is dependent on recognition.

8. 6.8 polar regions
There has been contentions to the ownership. Contiguity principle operates- whereby the occupying state may claim territory which is geographically pertinent to its area of lodgement.
A number of conventions have been drafted given the use of these regions as navigation under frozen water is possible
For the Antarctica, key article prohibits any activity relating to mineral resources other than scientific research.