History · Federated States of Micronesia

Micronesia: The Federation of the Carolines

Four island states — Yap of the stone money, Pohnpei of Nan Madol, Chuuk of the great lagoon, and Kosrae — ruled in turn by Spain, Germany, Japan and the US, and now a nation in free association with Washington

By Worldlore Editorial · 10 September 2026

Walls of stacked black basalt columns rising from shallow water among mangroves
Nan Madol, off Pohnpei — about 100 artificial islets of stacked basalt built in a lagoon between roughly 1200 and 1600 CE, the seat of the Saudeleur dynasty. (Patrick Nunn / Wikimedia Commons · CC BY-SA 4.0)

Four states, one federation

The Federated States of Micronesia is a union of four island states — Yap, Chuuk, Pohnpei and Kosrae — scattered across some 2,700 kilometres of the western Pacific, in the group historically called the Caroline Islands. About 100,000 people live on roughly 700 square kilometres of land inside an ocean territory of 2.6 million. The four states are strikingly different from one another, with their own languages and traditions, and the country is bound together loosely — and bound tightly, by a Compact of Free Association, to the United States.

A short history

  1. c. 1000 BCE onward

    Settlement

    Austronesian voyagers reach the Carolines.

  2. c. 1200–1600 CE

    Nan Madol

    The Saudeleur dynasty builds its stone city off Pohnpei.

  3. 16th century

    Spanish claim

    Rarely enforced for 300 years.

  4. 1899

    Germany

    Buys the Carolines from Spain.

  5. 1914

    Japan

    Seizes and later fortifies the islands.

  6. 1944

    Operation Hailstone

    The US destroys the Japanese fleet base at Truk.

  7. 1947

    US Trust Territory

    The Carolines are administered toward self-government.

  8. 1979

    The FSM

    The four Caroline districts form a federation.

  9. 1986

    Free association

    The Compact with the United States takes effect.

Stone money and a stone city

Austronesian voyagers settled the Carolines two to three thousand years ago, and the outer islands preserved some of the last living traditions of instrument-free ocean navigation in the Pacific. The islands developed distinct societies.

Yap and Pohnpei

A thatched Yapese community house with several large stone discs, some over a metre across, standing on end nearby
A Yapese community house with rai — stone money, giant limestone discs quarried on Palau and carried by canoe, still used ceremonially. Yap once headed a tribute network across the outer islands. (NOAA / Wikimedia Commons)
An aerial view of a barrier reef enclosing a wide blue lagoon dotted with islands
Chuuk Lagoon, one of the largest in the world. Chuuk is the most populous of the four FSM states. (Matt Kieffer / Wikimedia Commons)

Four flags in a century

Spain claimed the Carolines from the 16th century but barely governed them. After the Spanish–American War, Spain sold the islands to Germany in 1899; Germany worked them for copra through trading firms and crushed a 1910 rebellion on Pohnpei. Japan seized the German islands in 1914, held them under a League of Nations mandate, and — especially in the 1930s — colonised and fortified them, with Japanese settlers outnumbering islanders in some places. Truk Lagoon became the main forward base of the Japanese Combined Fleet.

A scuba diver with a camera hovering over stacked shells in the hold of a sunken ship
A wreck in Truk Lagoon. A US carrier raid in February 1944, Operation Hailstone, sank dozens of Japanese ships here; the wrecks are now a war grave and a famous dive site. (Aquaimages / Wikimedia Commons)

Trust Territory, and the Compact

After the war the Carolines became part of the US-administered UN Trust Territory of the Pacific Islands, run toward eventual self-government. The four Caroline districts drafted a constitution in 1978 and formed the Federated States of Micronesia; the Marshalls, Palau and the Northern Marianas went their own ways.

Low modern government buildings set among green hills at Palikir on Pohnpei
Palikir, the FSM capital, on Pohnpei. The federal government is deliberately weak; most power, and most identity, rests with the four states. (Wikimedia Commons)

The Compact of Free Association with the United States took effect in 1986: the US handles defence and provides economic aid that is a large share of the FSM budget, and FSM citizens may live and work freely in the United States. The Compact's economic terms were renegotiated in 2003 and again in 2023, the latter amid US concern about growing Chinese influence in the Pacific.

Micronesia now

The economy leans heavily on US grants, on fees from foreign tuna fleets, and on subsistence farming and fishing, with some tourism. A large and growing share of Micronesians live in the US, especially Guam and Hawaii. The four states retain their own strong identities, and Chuuk has periodically raised the idea of seceding. Low-lying atolls in Chuuk and Yap states are exposed to rising seas.

What Micronesia carries

Micronesia's four states built, on their own, some of the largest constructions in the pre-modern Pacific — Nan Madol, the Yap tribute network — and then spent a century being handed between four foreign powers. The federation of 1979 was an attempt to face the outside world as one, while leaving each island most of its autonomy. The Compact keeps that arrangement viable, and keeps Micronesia firmly in the American orbit.

Explore the destination