Four island groups — Yap, Chuuk, Pohnpei, and Kosrae — scattered across the western Pacific's Caroline Islands, each with its own language and political tradition, never unified under a single flag until the twentieth century forced one power after another onto them: Spain, then Germany, then Japan, then the United States, in a rapid four-power relay spanning barely sixty years. Independence in 1986 finally gave the four states one flag of their own choosing.
No other page in this atlas changes hands so many times in so short a span. The Caroline Islands passed from Spanish to German to Japanese to American administration entirely within one human lifetime, each transfer decided in distant treaty rooms and war rooms rather than on the islands themselves — a pattern common across the Pacific but rarely this compressed.
Scope of this page: the territory of the present-day Federated States of Micronesia (Yap, Chuuk, Pohnpei, and Kosrae), pre-1885 to present, six entries. Palau, administered alongside these islands under Spain, Germany, and Japan, splits into its own separate trust-territory district after 1947 and is not covered here — see Palau's own page in this atlas. Part of a larger atlas — see the linked pages at the bottom.
Four islands, one relay of flags
The real, correctly-positioned coastlines of Yap, Chuuk, Pohnpei, and Kosrae, spread across roughly 1,700 miles of open Pacific — every power that held one held all four at once, so there's no genuine internal split to show. Press play, or drag the slider, to watch the same four-power relay the timeline below tells in words.
All four states changed hands together, every time. Spain, Germany, Japan, and the US Trust Territory each administered the whole Caroline Islands group (minus Palau) as one unit — no documented period exists where one of these four islands flew a different flag than the other three. The map below shows each island's own real traced coastline, correctly positioned relative to the others, but drawn far larger than true scale (see the note below the map).
pre-1885
Indigenous island communities
Real traced coastlines for the main island of each state, plotted at their correct relative longitude and latitude — but each island is drawn roughly a hundred times larger than true relative scale (the true gap between Yap and Kosrae is about 1,700 miles of open ocean), so distances and island sizes are not proportional to each other. No internal split — see the rule box above for why.
light blue field, four white stars — one for each of the four states
1986 – present
Federated States of Micronesia
Independent state (free association)Tosiwo NakayamaSecular (no state religion)
Migration & conquest:Emigration: to the United States under the Compact of Free Association (1986–)
Ruling house:Nahnmwarki line of Isokelekel
Who & why: a constitution drafted in 1975 unites the four island states into a single federal government, and full independence follows in 1986 under a Compact of Free Association with the United States — the FSM runs its own government and foreign policy while the US retains defense responsibility and provides economic assistance, an arrangement renewed and updated in the decades since.
What it represents: the light blue field echoes the United Nations' own blue, a nod to the trusteeship the FSM emerged from; the four white five-pointed stars, arranged in a circle at the center, stand for the four constituent states — Yap, Chuuk, Pohnpei, and Kosrae — joined as equals around a common center.
Paint guide
Proportions10:19, adopted 1978, retained at independence.
LayoutLight blue field, four white five-pointed stars arranged in a circle at the center.
Light blue#6699CC
White (stars)#F4EFE1
the US flag, administering power — customarily flown with the UN flag
1947 – 1986
US-administered UN Trust Territory of the Pacific Islands
Trust territoryNo single ruler documentedSecular (no state religion)
Migration & conquest:Conquered by: United States (1944)Emigration: Japanese settlers repatriated (1945–46)
Ruling house:Nahnmwarki line of Isokelekel
Who & why: after Japan's defeat in World War II, the United Nations creates the Trust Territory of the Pacific Islands in 1947 and names the United States as administering authority, replacing Japan's mandate over the former German Micronesian islands. The Caroline Islands (excluding Palau, administered as its own separate district and later its own country) fall within this trusteeship, governed by the US Navy and then the Department of the Interior until self-government movements lead to the FSM's own 1979 constitution and 1986 independence.
What it represents: as the administering power, the United States flew its own stars-and-stripes over the territory, customarily alongside the blue UN flag that marked the islands' formal status as a UN trusteeship rather than an American possession outright — no distinct trust-territory flag of its own was adopted for daily use.
Paint guide
Proportions10:19 (US flag standard); shown simplified with a reduced star count.
LayoutThirteen alternating red-and-white stripes, blue canton with white stars (simplified grid here); customarily flown beside the UN flag over trust territories.
Canton blue#1E2F96
Red#A4302A
White#F4EFE1
the flag of Japan — white field, red disc (Hinomaru)
1914 – 1947
Japanese Micronesia
MandateEmperor Taishō (Yoshihito)State Shinto (Japan's own state religion)
Migration & conquest:Conquered by: Japan (1914)Immigration: Japanese & Okinawan settlers (1920s–40s)
Ruling house:Nahnmwarki line of Isokelekel
Who & why: Japan seizes Germany's Pacific island colonies at the outbreak of World War I in 1914, occupying the Caroline, Marshall, and Mariana Islands with almost no resistance. The League of Nations formalizes the arrangement in 1920 as the "South Seas Mandate" (Nan'yō Chō), and Japan governs, settles, and economically develops the islands for the next quarter-century. Truk Lagoon (Chuuk) becomes a major Japanese naval base and fleet anchorage in World War II, subjected to the devastating Allied air raid "Operation Hailstone" in February 1944 — the sunken wrecks it left are still a famous scuba-diving site today.
What it represents: the flag of Japan itself — the Hinomaru, a red sun disc on a white field — flew over the mandate as it did over the home islands, with no separate colonial flag issued for the South Seas Mandate.
Paint guide
Proportions2:3.
LayoutWhite field, centered red disc (radius = 3/10 of flag height).
White#F4EFE1
Red disc#BC002D
German colonial flag — white field, black-white-red canton and eagle badge
1899 – 1914
German Micronesia (Caroline Islands)
ColonyWilhelm IINo official state religion (Catholicism via earlier Spanish missions)
Ruling house:Nahnmwarki line of Isokelekel
Who & why: following Spain's defeat in the 1898 Spanish-American War, a financially strained Spain sells its remaining Pacific possessions — the Caroline, Mariana, and Palau Islands — to Germany in 1899 for 25 million pesetas. Germany administers the Carolines as part of the German New Guinea protectorate, largely through copra trading companies and a small colonial administration, until Japan's 1914 seizure ends German rule after only fifteen years.
What it represents: German colonial ensigns of the period carried a white field with the imperial black-white-red tricolor in the canton and the colony's own badge in the fly — shown here schematically, since no single Caroline-Islands-specific badge survives in wide documented use.
Paint guide
ProportionsNo fixed civil ratio recorded for the colonial ensign; shown at 3:2.
LayoutWhite field, black-white-red horizontal canton at the hoist, colonial eagle badge in the fly (schematic).
White#F4EFE1
Black#1A1A1A
Red#A4302A
the Spanish flag of the era — red-yellow-red, yellow band double width
Who & why: Spain and Germany both claim the Caroline Islands in the early 1880s; Pope Leo XIII, asked to arbitrate the dispute in 1885, recognizes Spanish sovereignty while granting Germany trading and commercial rights. Spain formally administers the islands as part of the Spanish East Indies from 1885, but its presence is thin — a handful of garrisons and Catholic missionaries rather than a settled colonial bureaucracy — before it sells the islands outright to Germany in 1899.
What it represents: the Spanish national flag of the period — red-yellow-red horizontal bands, the yellow band double the width of each red one — flew over Spain's Pacific possessions as it did over the rest of the Spanish East Indies, without a distinct colonial variant for the Carolines.
Paint guide
Proportions2:3.
LayoutHorizontal red-yellow-red bands, yellow band double the height of each red band (1:2:1).
Red#A4302A
Yellow#F4C542
placeholder — pre-contact era, four distinct societies, no single flag
pre-1885
Indigenous Chuukese, Pohnpeian, Yapese, and Kosraean communities
Indigenous nations, pre-contactNo single ruler documentedTraditional beliefs, varied by island (no state religion)
Ruling house:Saudeleur dynastyNahnmwarki line of Isokelekel
Who & why: each of the four island groups that now make up the FSM — Yap, Chuuk, Pohnpei, and Kosrae — developed and maintained its own distinct language, chiefly political structure, and navigational and social traditions for centuries before Spanish contact, with no overarching authority linking them. Pohnpei is home to Nan Madol, a monumental complex of nearly a hundred artificial islets built from massive basalt columns off its eastern shore, raised by the Saudeleur dynasty beginning around the twelfth century as a ceremonial and political center — one of the Pacific's most striking and least-known ancient sites, and unlike anything else built by a pre-contact Pacific Island society.
What it represents: no single flag, and no single polity, existed across the four island groups before colonization; each maintained its own separate customs of authority and identity rather than a shared territorial symbol. Shown here honestly blank rather than invented.
Paint guide
ProportionsN/A — no attested flag.
Reading the tags
Indigenous nations, pre-contact — no single flag, no colonial rule
Colony — under a foreign power's direct administration
Mandate — administered under League of Nations authority
Trust territory — administered under United Nations authority
Independent state (free association) — sovereign, in compact with another state
Leader — the named ruler most associated with the era's start
State religion — the official/established faith, not the population's
Find the records
Family history research for Micronesia lives in a different project, Record Atlas, which maps which archive actually holds the paper for a given place and era.