Borders and Territorial Boundaries

Concept International Law Preferred

Lines that mark the limits of a State's territory and the legal rules that protect their stability.

Independent referenceNot an official or legal definition
Sources citedSee the sources at the end of this page
Status Under reviewLast updated 11 October 2026
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Definition

In plain language

Borders are the lines where one country's territory ends and another's begins. International law treats them as stable, so they should not be changed by force.

Academic definition

International law protects territorial boundaries through the prohibition of force against territorial integrity (UN Charter Article 2(4)), the principle of uti possidetis juris for newly independent States and the presumption that established boundaries are permanent, stated by the ICJ in the Temple of Preah Vihear case (1962) and in Libya/Chad (1994). Boundaries can be changed by agreement, and the Helsinki Final Act of 1975 allows peaceful change by agreement while treating frontiers as inviolable. The location of boundaries is set by treaty, adjudication, or long-standing practice.

Classification

Term type
Concept
Category
International Law
Subject field
International Law
Subfield
Territory and Boundaries
Difficulty level
Beginner
Grammatical category
noun phrase

Language variants

Alternative terms
  • frontiers
  • state boundaries
Non-preferred terms
  • not_applicable
Abbreviations
  • not_applicable
Acronyms
  • not_applicable
Native terms
  • not_applicable
Transliteration
not_applicable
Pronunciation
not_applicable

Context

Legal effect: Binding

Scope

Covers land and territorial boundaries in general; delimitation, demarcation and maritime boundaries are dealt with in other records.

Legal context

UN Charter Article 2(4); the principle of stability of boundaries recognised by the ICJ in Temple of Preah Vihear (1962), Burkina Faso/Mali (1986) and Libya/Chad (1994); the Vienna Convention on the Law of Treaties Article 62(2)(a) excludes boundary treaties from fundamental change of circumstances.

Diplomatic context

Boundary disputes are managed by joint commissions, arbitration or ICJ cases, and States reaffirm borders in peace settlements and regional charters.

Institutional context

Handled by foreign ministries, boundary commissions, the ICJ and arbitral bodies.

Historical context

Colonial boundaries became the starting point for new States in Africa and Latin America, and the Organization of African Unity accepted them in its 1964 resolution on border disputes.

Why it matters

Stable borders protect against territorial conflict, but disagreement over their location is a common cause of disputes.

Usage

Register: Legal

Usage note

'Border' is the everyday word; 'boundary' and 'frontier' are used in legal and technical texts.

Example

The two States signed a treaty confirming their territorial boundaries and creating a joint commission to mark them.

Example scenario

After independence, State A and State B disagree about a stretch of their shared border. They take the case to the ICJ, which applies the colonial-era boundary under uti possidetis and draws a line accordingly.

Common misuse

Using 'border' and 'boundary' as having different legal consequences; the legal rules apply to both.

Not to be confused with

  • Boundary delimitation
  • Demarcation line
  • Maritime boundary

Sources

  1. Charter of the United Nations (1945), United Nations, Article 2(4). un.org
  2. Official definition. not_found_in_source
  3. Treaty reference. legal.un.org
  4. Shaw, International Law. not_found_in_source
  5. not_found_in_source. not_found_in_source

Source type: Treaty. Source reliability: Primary.

This entry is an independent reference definition, not an official or legally binding text. Where an official definition exists, it is linked above and is authoritative. Read our methodology.

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