Explainer

Why boundaries differ between maps

Maps of the same area can show treaty lines, administrative borders, lines of control or cultural regions. They answer different questions.

2 min read · updated 15 September 2026

Different kinds of line

A line on a map can mean an internationally recognised frontier, an internal administrative boundary, a ceasefire or control line, an area defined in a treaty that never took effect, or the approximate extent of a language or culture. Two maps can both be accurate and still disagree because they show different things.

Treaties have defined areas that never became borders. The 1920 Treaty of Sèvres described a Kurdish autonomy area by reference to rivers and future frontiers, but the treaty never took effect.[1]

When internal boundaries become frontiers

In the breakup of Yugoslavia, the Arbitration Committee held that former internal boundaries become international frontiers unless otherwise agreed, and that self-determination should not change existing frontiers without agreement.[2][3]

Disputed and controlled areas

Iraq’s Constitution called for a referendum on Kirkuk and other disputed territories by 2007 that had not been held a decade later, and the region’s 2017 referendum question itself extended to disputed areas outside its administration.[4][5] In Western Sahara, a berm divides the forces of the two sides, but it is not the boundary of the Territory the UN lists.[6][7]

How this atlas handles maps

Case markers on the atlas map are approximate points that say nothing about boundaries or sovereignty. Any boundary layer is reviewed separately, labelled with what it represents and its source, and never replaces the written explanation of a disputed status.

Sources for this page

Each number marks a specific claim. Notes give the source, its locator and how it relates to the claim.

  1. 1.

    Claim: The Treaty of Sèvres defined a Kurdish autonomy area by reference to the Euphrates, the future southern boundary of Armenia and Turkey’s frontiers with Syria and Mesopotamia.

    • Principal Allied Powers and Turkey, Treaty of Peace with Turkey, signed at Sèvres, August 10, 1920 (His Majesty’s Stationery Office, 1920) link, art. 62, p. 21. Government perspective or primary official source Source record
  2. 2.

    Claim: In Opinion No. 3 the Committee stated that, except where otherwise agreed, the former internal boundaries become frontiers protected by international law, drawing on the principle of uti possidetis. Attributed to Arbitration Committee of the Conference on Yugoslavia

    • Pellet, Alain, The Opinions of the Badinter Arbitration Committee: A Second Breath for the Self-Determination of Peoples, European Journal of International Law (1992) link, appendix, Opinion No. 3, p. 185. Source record
  3. 3.

    Claim: In Opinion No. 2 the Committee stated that the right to self-determination must not involve changes to existing frontiers at the time of independence except where the states concerned agree otherwise, and that ethnic, religious or language communities within a state have the right to recognition of their identity under international law. Attributed to Arbitration Committee of the Conference on Yugoslavia

    • Pellet, Alain, The Opinions of the Badinter Arbitration Committee: A Second Breath for the Self-Determination of Peoples, European Journal of International Law (1992) link, appendix, Opinion No. 2, p. 184. Source record
  4. 4.

    Claim: Iraq’s Constitution required a referendum in Kirkuk and other disputed territories by the end of 2007, which had not been held by 2017.

    • Republic of Iraq, Iraq’s Constitution of 2005 (Constitute Project, 2005) link, art. 140. Government perspective or primary official source Source record
    • United Nations Secretary-General, Report of the Secretary-General pursuant to resolution 2367 (2017) (United Nations, 19 October 2017) link, para. 9, p. 2. Source record
  5. 5.

    Claim: The question in the Kurdistan Region’s 2017 referendum, in the UN’s translation, asked about the independence of the region “and the Kurdistani areas (disputed areas) outside the administration of the region”.

    • United Nations Secretary-General, Report of the Secretary-General pursuant to resolution 2367 (2017) (United Nations, 19 October 2017) link, para. 2, p. 1. Source record
  6. 6.

    Claim: In Western Sahara a sand wall known as the berm separates Moroccan and Frente POLISARIO military forces.

    • United Nations Mission for the Referendum in Western Sahara, MINURSO: Background (United Nations) link, para. 11. Source record
  7. 7.

    Claim: Morocco administers Western Sahara west of the berm in fact but is not listed by the UN as the Territory’s administering Power.

    • United Nations Office of Legal Affairs, Letter dated 29 January 2002 from the Under-Secretary-General for Legal Affairs, the Legal Counsel, addressed to the President of the Security Council (United Nations, 12 February 2002) link, para. 7, p. 2. Source record
    • United Nations Secretary-General, Situation concerning Western Sahara: report of the Secretary-General (United Nations, 30 September 2025) link, paras. 38 and 41, pp. 6–7. Source record

Source note

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