Global Decolonization Map, 1921–1990: From Colonial Rule to Independence

About This Chart

Data Visualization Method

• Data: Curated colonial-status records for present-day countries — the start and the selected end of each country's mapped colonial or dependency relationship — rather than year-by-year field observations.
• Period and area: 1921 to 1990, covering 103 present-day countries that were still under the selected colonial or dependency status at the opening 1921 frame.
• Selection: Only countries still under that status at the start of the 1921 timeline are highlighted. Countries that had already completed the relevant transition before 1921 — much of Latin America, for example — appear as neutral geographic context rather than as part of the animated set.
• Processing: Each country is assigned a single transition year. For every year before it, the country reads as under colonial rule; from that year onward it reads as independent and stays independent for the rest of the timeline. Present-day boundaries are used throughout.
• Chart form: An animated region map driven by a year slider. Color encodes only the two states — under colonial rule and independent — while country size reflects geography alone and carries no ranking.

Creator's Note

The aim was to place the twentieth-century decolonization wave on a single comparable frame, so the shift can be read spatially rather than as a list of separate dates. Each country is indexed to its present-day outline, which lets a contemporary viewer recognize today's map while watching when a given territory's mapped status changed.

The moment worth watching is not any one country but the collective change of color: colonial rule stays geographically broad across the early timeline, then the transitions accelerate through the mid-century decades and sweep across much of Africa and Asia. The map records where and when these selected transitions occurred — a starting point for questions about how that wave moved, not a settled account of why each country became independent.

Data Sources

• Colonial Dates Dataset (COLDAT 3.0), via Our World in Data — the main structural base for the European overseas colonial cases.
• United Nations — Decolonization — used to cross-check the broader post-war framework and mandate or trust-territory histories, including Namibia as the 1990 endpoint.
• Supplementary historical records curated by aistockQ — added for non-European colonial rule and selected mandate or trust cases, including Japanese colonial rule over Korea.

Limitations

Historical decolonization rarely resolves to one clean date. A single country could pass through colony, protectorate, mandate, trust territory, occupation, staged constitutional independence or transfers of sovereignty. For this map, each country is assigned one editorially selected transition year, which should be read as the year chosen for this visualization — not as the single, universally agreed date on which every form of foreign control ended.

The geometry uses present-day country boundaries as an indexing device, not the actual borders of empires in any given year. Because of this, Korea is represented through the current South Korean and North Korean polygons; both switch in 1945 to mark the end of Japanese colonial rule over Korea, which is not a claim that two separate Korean states existed under that rule.

The dataset is a composite. It draws primarily on COLDAT, which covers European overseas empires, and is supplemented with curated records for non-European and mandate or trust cases. It is therefore not a one-to-one reproduction of any single source, and the provenance behind each case varies.

What This Chart Doesn't Show

Neutral, un-highlighted countries were not necessarily never colonized. Neutral here means only that a country falls outside this 1921–1990 set; many states, particularly across Latin America, had earlier colonial histories but reached independence before the timeline begins. The map is not a ranking, and a change to independent marks the selected formal transition — not the instant end of every political, economic or military dependency.

The animation closes with Namibia in 1990 because that is the final transition included in this chart, not because colonial situations everywhere ceased that year; the United Nations still lists Non-Self-Governing Territories today. And the map shows when and where the selected transitions occurred, not why any individual country became independent.