The Filibuster War of 1856–57, known in Costa Rica as the Campaña Nacional (National Campaign), was the war Costa Rica and its Central American neighbors fought against William Walker, an American adventurer who had seized control of Nicaragua with a private army of “filibusters.” Costa Rica beat Walker’s men at Santa Rosa on March 20, 1856, and at Rivas on April 11, 1856, then helped cut his supply route on the San Juan River. Walker surrendered on May 1, 1857. The war gave Costa Rica its national hero, the drummer boy Juan Santamaría, and it remains the country’s defining national story.
This guide is for travelers and history readers who want the short version: what happened, why it matters to Costa Ricans today and where you can see the history for yourself.
| Filibuster War | At a glance |
|---|---|
| When | 1856–1857 (Walker arrived in Nicaragua in 1855) |
| Who | Costa Rica and the other Central American republics vs. William Walker’s filibusters |
| Key battles in Costa Rica’s story | Santa Rosa (March 20, 1856) and Rivas, Nicaragua (April 11, 1856) |
| Costa Rica’s leader | President Juan Rafael Mora Porras |
| National hero | Juan Santamaría, killed at Rivas |
| Hidden cost | A cholera epidemic that killed roughly 1 in 10 Costa Ricans |
| Remembered with | The April 11 holiday, the international airport’s name and monuments in San José and Alajuela |
Background
What Was the Filibuster War?
In the 1850s, a “filibuster” was a private adventurer who raised an armed expedition to take over a foreign country without his own government’s approval. The word comes from the Spanish filibustero, meaning freebooter.
William Walker was the best known. Born in Tennessee and trained as a doctor and lawyer, he had already tried to seize parts of Mexico. In June 1855, he landed in Nicaragua with a small band of American mercenaries to fight for one side in a Nicaraguan civil war. Within months he controlled the country, and in July 1856 he had himself inaugurated as president. Among other decrees, he legalized slavery.
Nicaragua mattered because it held a key route between the Atlantic and Pacific: steamers up the San Juan River and across Lake Nicaragua, used by thousands of gold-rush travelers heading to California. Walker’s ambitions threatened every country in Central America, and Costa Rica, sharing the San Juan border, moved first.
Timeline
Filibuster War Timeline
- June 1855: Walker lands in Nicaragua and soon takes control of the government.
- Late February 1856: Costa Rica declares war, and President Juan Rafael Mora Porras calls Costa Ricans to arms.
- March 20, 1856: Costa Rican troops rout a filibuster column at the Hacienda Santa Rosa in Guanacaste.
- April 11, 1856: Costa Rica wins the Second Battle of Rivas in Nicaragua; Juan Santamaría dies setting fire to the filibusters’ stronghold.
- April–June 1856: Cholera spreads from Rivas with the returning army and kills about one-tenth of Costa Rica’s population.
- July 1856: Walker is inaugurated president of Nicaragua.
- Late 1856: Costa Rican forces retake the transit route and the San Juan River steamers, cutting Walker off from reinforcements.
- May 1, 1857: Walker, besieged at Rivas by the allied Central American armies, surrenders to U.S. Navy Commander Charles Henry Davis and leaves for the United States.
- 1860: Walker returns to Central America and is executed by firing squad in Trujillo, Honduras, on Sept. 12. Mora, overthrown in 1859, is executed in Puntarenas on Sept. 30 after a failed attempt to return to power.
Santa Rosa
The Battle of Santa Rosa
After Costa Rica declared war, Walker sent a column under Louis Schlessinger into Guanacaste. The filibusters camped at the Hacienda Santa Rosa, a cattle ranch near today’s border with Nicaragua. On March 20, 1856, a much larger Costa Rican force led by the president’s brother, José Joaquín Mora, attacked. The fight lasted only about 14 minutes, and the filibusters fled.
The ranch house, La Casona, still stands inside Santa Rosa National Park. It burned in 2001 and was rebuilt, and it’s the most direct place to connect with the war in Costa Rica. Read more about Guanacaste’s history and culture.
Rivas
The Battle of Rivas and Juan Santamaría
Mora then marched about 3,000 troops into Nicaragua. On April 11, 1856, they fought Walker’s men in the town of Rivas. Filibuster sharpshooters held a large building, the Mesón de Guerra, and several attempts to burn them out failed. Juan Santamaría, a young drummer from Alajuela, volunteered to carry a torch to the building. He was shot but set it on fire, and the filibusters fell back. Costa Rica won the battle.
Santamaría became the country’s national hero. April 11 is a public holiday, and Costa Rica’s main international airport near Alajuela bears his name. Read the full story of Juan Santamaría.
The cost
Cholera: The War’s Hidden Toll
The victory at Rivas came at a terrible price. The dead were thrown into the town’s wells, and cholera broke out. Soldiers carried it home, and the epidemic killed about 9,600 Costa Ricans in roughly ten weeks, around one-tenth of the population. Far more Costa Ricans died of cholera than in battle.
Mora was blamed for the deaths and the war debts. He was overthrown in 1859 and executed the following year. Costa Ricans have since come to honor him as the leader who saved the country’s independence.
Legacy
Why the Filibuster War Matters in Costa Rica Today
Costa Rica gained independence from Spain in 1821 without a fight. The Filibuster War was the first time its people went to war for the country, and it gave Costa Ricans a shared story, heroes and dates that still shape national identity. Schoolchildren learn it in detail, and April 11 brings parades, especially in Alajuela.
Costa Rica later abolished its army in 1948, almost a century after the war. The two are separate chapters; read why Costa Rica has no army. For other national dates, see our guides to Costa Rica Independence Day and Costa Rica holidays and celebrations.
Visit
Where to See Filibuster War History in Costa Rica
- Museo Histórico Cultural Juan Santamaría, Alajuela: a free museum in downtown Alajuela with exhibits on Santamaría and the campaign against Walker. It’s about 10 minutes from the international airport, so it fits a first or last day. Hours vary, so check before you go.
- National Monument, San José: the bronze and stone Monumento Nacional in Parque Nacional, inaugurated in 1895 and made by the French sculptor Louis-Robert Carrier-Belleuse. Its figures represent the five Central American republics driving out the filibuster. See our San José guide.
- La Casona, Santa Rosa National Park, Guanacaste: the rebuilt ranch house where the Battle of Santa Rosa was fought, inside the park’s dry forest.
For more history stops near the capital, see our list of museums to visit from San José.
FAQ
Filibuster War FAQ
What was the Filibuster War?
A war in 1856–57 in which Costa Rica and the other Central American republics fought William Walker, an American adventurer who had taken control of Nicaragua with a private army of filibusters.
Who won the Filibuster War?
The Central American allies. Walker surrendered on May 1, 1857, and left Nicaragua. Costa Rica played a leading role, winning at Santa Rosa and Rivas and cutting Walker’s route on the San Juan River.
Who was William Walker?
A Tennessee-born doctor, lawyer and adventurer who led private military expeditions into Mexico and Nicaragua. He made himself president of Nicaragua in 1856 and was executed in Honduras in 1860.
Who was Juan Santamaría?
A young drummer from Alajuela who died setting fire to the filibusters’ stronghold at the Battle of Rivas on April 11, 1856. He is Costa Rica’s national hero.
Why is it called the National Campaign in Costa Rica?
Costa Ricans call the 1856–57 war the Campaña Nacional because the whole country mobilized to defend its independence.
Is April 11 a holiday in Costa Rica?
Yes. April 11, Juan Santamaría Day, marks the Battle of Rivas and is a national holiday, with parades in Alajuela.
The short version
In 1856–57, Costa Rica and its neighbors fought William Walker, who had seized Nicaragua.
Costa Rica won at Santa Rosa and Rivas, where Juan Santamaría became the national hero, but cholera killed about one in 10 Costa Ricans.
See the history at the Juan Santamaría museum in Alajuela, the National Monument in San José and La Casona at Santa Rosa.