Fort Napoléon occupies a commanding height above the harbor of Terre-de-Haut in Les Saintes, where European empires competed for control of Guadeloupe's sea lanes. France colonized the islands in the seventeenth century, and the sheltered roadstead became strategically important during wars with Britain. A first substantial work, Fort Louis, was built on the hill in the late 1770s. It helped guard the anchorage shortly before the Battle of the Saintes in April 1782, when Admiral George Rodney's British fleet defeated the French fleet of the Comte de Grasse nearby and disrupted plans for an attack on Jamaica.

The fort's name changed with France's political regimes. It became Fort Napoléon during the First Empire, but British forces captured Les Saintes in 1809 and destroyed the position. Guadeloupe changed hands repeatedly during the Revolutionary and Napoleonic wars before returning permanently to France in 1816. The ruined hilltop still controlled views across the channel, so French authorities later decided to build a stronger masonry work suited to nineteenth-century artillery and imperial defense.

Construction of the present fort proceeded from 1844 to 1867, during the reigns of Louis-Philippe and Napoleon III. Thick stone walls enclosed barracks, magazines, cisterns, firing positions, and a central courtyard. The new complex inherited the Napoléon name but never fired in battle. Steam power, longer-range naval guns, and changing strategy soon reduced the importance of such isolated harbor forts. Its garrison nevertheless represented French authority in a Caribbean colony whose economy and social order had been shaped by slavery.

France abolished slavery in Guadeloupe in 1848 while construction was underway. The fort's military story must therefore be understood alongside emancipation, colonial labor, and the struggles of formerly enslaved people to define freedom. After losing its primary defensive role, the building served at times as a detention site. During the Second World War, Guadeloupe initially remained under the Vichy-aligned administration of Governor Constant Sorin before local resistance and regional events brought the colony to Free France in 1943; the fort belonged to that wider militarized landscape even without becoming a battlefield.

Abandonment and tropical weather damaged the complex until local preservation efforts gave it a new purpose. The Association saintoise de protection du patrimoine took responsibility around 1980, restoring rooms and developing a museum devoted to the history, naval battles, traditions, and natural environment of Les Saintes. A botanical garden now surrounds the masonry, and the fort was protected as a historic monument in 1997. Fort Napoléon's layered history—eighteenth-century rivalry, British destruction, nineteenth-century rebuilding, emancipation, detention, and community restoration—explains why a fort that never fought in its present form remains one of Guadeloupe's most revealing colonial sites. The museum also interprets the Battle of the Saintes from multiple positions within an imperial war fought largely by sailors, soldiers, and colonial populations who had little control over strategy. The view from the ramparts makes the geography of the 1782 battle understandable: narrow channels, high islands, and the protected bay explain why Les Saintes mattered to fleets operating between Guadeloupe and Dominica.