Mont-Saint-Michel (French pronunciation: [lə mɔ̃ sɛ̃ miʃɛl]; Norman: Mont Saint Miché; English: Saint Michael's Mount) is a tidal island and mainland commune in Normandy, France.

The island lies approximately one kilometre (one-half nautical mile) off France's north-western coast, at the mouth of the Couesnon River near Avranches and is 7 hectares (17 acres) in area. The mainland part of the commune is 393 hectares (971 acres) in area so that the total surface of the commune is 400 hectares (990 acres). As of 2019, the island had a population of 29.

The commune's position—on an island just a few hundred metres from land—made it accessible at low tide to the many pilgrims to its abbey, and defensible as the incoming tide stranded, drove off, or drowned would-be assailants. The island remained unconquered during the Hundred Years' War. A small garrison fended off a full attack by the English in 1433. Louis XI recognised the benefits of its natural defence and turned it into a prison. The abbey was used regularly as a prison during the Ancien Régime.

Mont-Saint-Michel and its surrounding bay were inscribed on the UNESCO list of World Heritage Sites in 1979 for its unique aesthetic and importance as a Catholic site. It is visited by more than three million people each year, and is the most-visited tourist attraction in France outside of Paris. Over 60 buildings within the commune are protected as historical monuments.

In 2023, President Macron marked 1,000 years of the abbey, and the success of the hydraulic dam project and the elevated pedestrian bridge in restoring water flow in the bay, making the mount an island again.

Now a rocky tidal island, the mount occupied dry land in prehistoric times. As sea levels rose, erosion reshaped the coastal landscape, and several outcrops of granite emerged in the bay, having resisted the wear and tear of the ocean better than the surrounding rocks. These included Lillemer, Mont Dol, Tombelaine (the island just to the north), and Mont Tombe, later called Mont-Saint-Michel.

Mont-Saint-Michel consists of leucogranite which solidified from an underground intrusion of molten magma about 525 million years ago, during the Cambrian period, as one of the younger parts of the Mancellian granitic batholith. Early studies of Mont-Saint-Michel by French geologists sometimes describe the leucogranite of the Mont as "granulite", but this granitic meaning of granulite is now obsolete.

The mount has a circumference of about 960 m (3,150 ft) and its highest point is 92 m (302 ft) above sea level.

The tides vary greatly, at roughly 14 metres (46 ft) between highest and lowest water marks. Popularly nicknamed "St. Michael in peril of the sea" by medieval pilgrims making their way across the flats, the mount can still pose dangers for visitors who avoid the causeway and attempt the hazardous walk across the sands from the neighbouring coast.

Polderisation and occasional flooding have created salt marsh meadows that were found to be ideally suited to grazing sheep. The well-flavoured meat that results from the diet of the sheep in the pré salé (salt meadow) makes agneau de pré-salé ('salt-meadow / salt-marsh lamb'), a local specialty that may be found on the menus of restaurants that depend on income from the many visitors to the mount.

The connection between Mont-Saint-Michel and the mainland has changed over the centuries. Previously connected by a tidal causeway uncovered only at low tide, this was converted into a raised causeway in 1879, preventing the tide from scouring the silt around the mount. The coastal flats have been polderised to create pastureland, decreasing the distance between the shore and the island, and the Couesnon river has been canalised, reducing the dispersion of the flow of water. These factors have all encouraged silting-up of the bay.

In June 2006, French prime minister Dominique de Villepin and regional authorities announced a €200 million project (Projet Mont-Saint-Michel) to build a hydraulic dam using the waters of the Couesnon and the tides to help remove the accumulated silt, and to make Mont-Saint-Michel an island again. The construction of the dam began in 2009. The project included the removal of the causeway and its visitor car park. Since April 2012, the new car park on the mainland has been located 2.5 kilometres (1+1⁄2 mi) from the island. Visitors can walk or use shuttles to cross the causeway.

In July 2014, the new bridge, by architect Dietmar Feichtinger, was opened to the public. The light bridge allows waters to flow freely around the island and improves the efficiency of the now-operational dam. The bridge, which cost €209 million, was opened by President François Hollande.

On rare occasions, tidal circumstances produce an extremely high "supertide". The new bridge was completely submerged on 21 March 2015 by the highest sea level, a once-in-18-years occurrence, as crowds gathered to snap photos.

Before the construction of the first monastic establishment in the 8th century, the island was called Mont Tombe (Latin: tumba). According to a legend, the archangel Michael appeared in 708 to Aubert of Avranches, the bishop of Avranches, and instructed him to build a church on the rocky islet.

Unable to defend his kingdom against the assaults of the Vikings, the king of the Franks agreed to grant the Cotentin Peninsula and the Avranchin, including Mont-Saint-Michel traditionally linked to the city of Avranches, to the Bretons in the Treaty of Compiègne. This marked the beginning of a brief period of Breton possession of the Mont. In fact, these lands and Mont-Saint-Michel were never really included in the duchy of Brittany. Around 989–990 these traditional bishoprics, dependent of the archbishopric of Rouen and that had been left vacant during the time of the Viking raids, regained their bishops.

The mount gained strategic significance again in 933 when William I Longsword annexed the Cotentin Peninsula from the weakened Duchy of Brittany. This made the mount definitively part of Normandy, and is depicted in the Bayeux Tapestry, which commemorates the Norman Conquest. Harold Godwinson is pictured on the tapestry rescuing two Norman knights from the quicksand in the tidal flats during the Breton–Norman war. Norman ducal patronage financed the spectacular Norman architecture of the abbey in subsequent centuries.

In 1067, the monastery of Mont-Saint-Michel gave its support to William the Conqueror in his claim to the English throne. This he rewarded with properties and grounds on the English side of the Channel, including a small island off the southwestern coast of Cornwall which was modelled after Mont-Saint-Michel and became a Norman priory named St Michael's Mount of Penzance.

During the Hundred Years' War, English forces unsuccessfully besieged Mont-Saint-Michel (which was under French control) twice. The first siege started in 1423, and was lifted the next year. In 1433, an English force equipped with wrought-iron bombards and under the command of Thomas Scales, 7th Baron Scales again besieged the island. It was likewise lifted the next year. Scales's men abandoned two bombards they had used during the siege on 17 June 1434; they were recovered by the French and are currently on display.

When Louis XI of France founded the Order of Saint Michael in 1469, he intended that the abbey church of Mont-Saint-Michel become the chapel for the order, but because of its great distance from Paris, his intention could never be realized.

The wealth and influence of the abbey extended to many daughter foundations, including St Michael's Mount in Cornwall. Its popularity and prestige as a centre of pilgrimage waned with the Reformation, and by the time of the French Revolution there were scarcely any monks in residence. The abbey was closed and converted into a prison, initially to hold clerical opponents of the republican regime. High-profile political prisoners followed. By 1836, influential figures—including Victor Hugo—had launched a campaign to restore what was seen as a national architectural treasure. The prison was closed in 1863.

In 1872, French architect of historic monuments Édouard Corroyer was responsible for assessing the condition of Mont-Saint-Michel. It took him about two years to convince his minister to classify it as a historic monument, and it was officially declared as such in 1874. From then on Corroyer, a member of the Academy of Fine Arts, devoted fifteen years of his life to the restoration of "la Merveille". Under his direction, gigantic works were undertaken, starting with the most urgent. He wrote four works on the building.

During the occupation of France in World War II, German soldiers occupied Mont-Saint-Michel, where they used St. Aubert church as a lookout post. The island was a major attraction for German tourists and soldiers, with around 325,000 German tourists from July 18, 1940, to the end of the occupation of France.

After the Allies' initial D-Day invasion of Normandy that began on June 6, 1944, many exhausted German soldiers retreated to strongholds like Mont-Saint-Michel. On August 1, 1944, a single American soldier – Private Freeman Brougher of Pennsylvania and the 72nd Publicity Service Battalion – reached and liberated Mont-Saint-Michel accompanied by two British reporters, Gault MacGowan of the New York Sun and Paul Holt with the London Daily Express. Jubilant crowds of locals greeted Brougher, Holt and MacGowan, and Brougher signed the Golden Book, the island's record of visiting nobility, at the mayor's invitation. The abbey was also used as a prison for the first time since the French Revolution when male collaborators with the Germans were jailed there.

Mont-Saint-Michel and its bay were added to the UNESCO list of World Heritage Sites in 1979, listed with criteria such as cultural, historical, and architectural significance, as well as human-created and natural beauty.

In June 2023, President Emmanuel Macron visited Mont-Saint-Michel to mark the 1,000-year anniversary of the abbey. He stated that the changes since the hydraulic dam and the new bridge opened have lessened the silting, making it an island again.

In the 11th century, William of Volpiano, the Italian architect who had built Fécamp Abbey in Normandy, was chosen by Richard II, Duke of Normandy, to be the building contractor. He designed the Romanesque church of the abbey, daringly placing the transept crossing at the top of the mount. Many underground crypts and chapels had to be built to compensate for this weight. These formed the basis for the supportive upward structure that can be seen today. Today Mont-Saint-Michel is seen as a building of Romanesque architecture.

Robert de Thorigny, a great supporter of Henry II of England, who was also Duke of Normandy, reinforced the structure of the buildings and built the main façade of the church in the 12th century. In 1204, Guy of Thouars, regent for the Duchess of Brittany, as vassal of the King of France, undertook a siege of the Mount. After setting fire to the village and massacring the population, he beat a retreat under the powerful walls of the abbey. The fire which he lit extended to the buildings, and the roofs fell prey to the flames. Horrified by the cruelty of his Breton ally, Philip Augustus offered Abbot Jordan a grant for the reconstruction of the abbey in the new Gothic architectural style.

Charles VI is credited with adding major fortifications to the abbey-mount, building towers, successive courtyards, and strengthening the ramparts.

• 
  10th century
• 
  11th to 12th century
• 
  17th to 18th century
• 
  19th to 21st century

The islet belongs to the French commune of Le Mont-Saint-Michel, in the département of Manche, in Normandy. The nearest significant town, with an SNCF train station, is Pontorson, with a population of slightly over 4,000. Mont-Saint-Michel belongs to the Organization of World Heritage Cities.

Historical population of Le Mont-Saint-Michel

Year Pop. ±% p.a. 1793 234 —     1800 234 +0.00% 1806 282 +3.16% 1821 304 +0.50% 1831 390 +2.52% 1836 385 −0.26% 1841 1,082 +22.96% 1846 1,100 +0.33% 1851 1,182 +1.45% 1856 1,153 −0.50% 1861 1,056 −1.74% 1866 203 −28.09%	Year Pop. ±% p.a. 1872 193 −0.84% 1876 184 −1.19% 1881 209 +2.58% 1886 211 +0.19% 1891 199 −1.16% 1896 230 +2.94% 1901 235 +0.43% 1906 238 +0.25% 1911 232 −0.51% 1921 230 −0.09% 1926 247 +1.44% 1931 250 +0.24%	Year Pop. ±% p.a. 1936 231 −1.57% 1946 186 −2.14% 1954 268 +4.67% 1962 132 −8.47% 1968 105 −3.74% 1975 114 +1.18% 1982 80 −4.93% 1990 72 −1.31% 1999 46 −4.86% 2007 41 −1.43% 2012 41 +0.00% 2017 30 −6.06%
From the year 1962 on: No double counting—residents of multiple communes (e.g., students and military personnel) are counted only once. Source: EHESS and Insee

Births

1956–1962	1962–1968	1968–1975	1975–1982	1982–1990	1990–1999
xx	13	16	8	6	4

Deaths

1956–1962	1962–1968	1968–1975	1975–1982	1982–1990	1990–1999
xx	6	6	4	5	3

Since June 2001, following the appeal addressed to them in 2000 by Jacques Fihey, Bishop of Coutances and Avranches, a community of monks and nuns of the Monastic Fraternities of Jerusalem, sent from the mother-house of St-Gervais-et-St-Protais in Paris, have been living as a community on Mont-Saint-Michel. They replaced the Benedictine monks who returned to the mount in 1966. They are tenants of the centre for national monuments and are not involved in the management of the abbey.

The community has seven sisters and four brothers. Their life revolves around prayer, work and fraternal life. The community meets four times a day to recite the liturgical office in the abbey, or in the crypt of Notre-Dame des Trente Cierges in winter. In 2012, the community undertook the renovation of a house on the mount, the Logis Saint-Abraham, which is used as a guest house for pilgrims on retreat.

• Robert of Torigni, famous abbot of the mount;
• The Duke of Chartres (later Louis-Philippe I) came to demolish the "iron cage";
• Louis Auguste Blanqui, political prisoner in the mount;
• Armand Barbès, political prisoner in the mount;
• La Mère Poulard, famous restaurant;
• Anne Boutiaut Poulard, creator of the Omelette de la mère Poulard.
• Tiphaine Raguenel, Breton noblewoman and astrologer.

The Mont-Saint-Michel has long "belonged" to some families who shared the businesses in the town and ran the village administration. Tourism is almost the sole source of income of the commune, bringing US$63 million to the small island in 2014. There are about 50 shops for three million tourists. About 25 people sleep every night on the mount, monks included, except for those in hotels. There are 132 hotel rooms within the island's walls. The main institutions are shared by:

• Eric Vannier, owner of the group Mère Poulard (holding half of restaurants, shops, hotels and three museums);
• Jean-Yves Vételé, CEO of Sodetour (five hotels, a supermarket and shops—all extramural—including Mercury Barracks);
• Patrick Gaul, former elected official, hotelier and intramural restaurateur;
• Independent merchants.

Overtourism is a problem for Mont-Saint-Michel, exascerbated by tourists mostly visiting on day-trips, which causes overcrowding from 10:00 to 16:00, especially in the summer. The Mont-Saint-Michel foundation has introduced measures to change this pattern and reduce daytime overcrowding, including by introducing free parking after 18:30, except during July and August.

• Hatsukaichi, Hiroshima, Japan, where Itsukushima Shrine, another UNESCO World Heritage Site, is located.

Historically, Mont-Saint-Michel was the Norman counterpart of St Michael's Mount in Cornwall, UK, which was given to the Benedictines, the religious order of Mont-Saint-Michel, by Edward the Confessor in the 11th century. The two mounts share the same tidal island characteristics and a similar conical shape, though Mont-Saint-Michel is much taller.

During the medieval period, pilgrims walked from Italy, Germany and England, as well as other parts of France. Such devotees were known as Miquelots. Modern pilgrims can follow the same routes. Ten hiking trails have been created that enable pilgrims from various European countries to retrace the path their ancestors may have taken during a medieval pilgrimage.

Part of the action in Helen MacInnes's 1943 film thriller Assignment in Brittany takes place at the Mont, including a dramatic nighttime chase across the sands. Peter Jackson is said to have taken inspiration from Mont-Saint-Michel in designing Gondor's capital city, Minas Tirith, in his 2003 film The Lord of the Rings: The Return of the King.

The site appears in the 2004 film Mickey, Donald, Goofy: The Three Musketeers.

The town and castle in the 2010 Disney hit film Tangled are based on Mont-Saint-Michel.

Terrence Malick's 2013 film To the Wonder features the abbey in its opening scenes.

Mindwalk is a 1990 feature film directed by Bernt Capra, adapted from his short story based on The Turning Point, a nonfiction book by physicist Fritjof Capra, his brother. Two friends, a poet and a politician, meet a physicist while exploring Mont-Saint-Michel, and engage in unexpectedly deep conversation.

The climax of the 2016 young adult novel The Inquisitor's Tale takes place in and around Mont-Saint-Michel, as the protagonists race over the causeway to the Abbey, pursued by the King's men.

Mont-Saint-Michel is a World Wonder in Civilization VI. Mont-Saint-Michel is featured in Onimusha 3: Demon Siege in which the abbey is overrun by demons in both the 16th and 21st centuries and subsequently destroyed.

A fictionalized version of the island, Beaumont-Saint-Denis, serves as the location for Sniper Elite 5's third mission. The castle is also the inspiration for the site of the climactic final battle in the air combat video game The Sky Crawlers: Innocent Aces, in which it is an abandoned enemy fortress with still-operational anti-air turrets; it also inspired Dark Souls' New Londo Ruins.

Mont-Saint-Michel appears at the end of the opening credits of The Walking Dead: Daryl Dixon, showing protagonists Daryl Dixon and Laurent looking out at it across zombie-infested tidelands. In "Deux Amours," it's revealed that Mont-Saint-Michel is the location of the Nest, their ultimate destination. In "Coming Home," Daryl's group finally reaches it.

The Mont-Saint-Michel–inspired village and castle from Tangled return in Rapunzel's Tangled Adventure and Tangled: Before Ever After.

• Aragonese Castle
• Carolingian architecture
• Carolingian art
• French Romanesque architecture
• Key Monastery
• La Mère Poulard
• Le Mont Saint Michel (clothing), clothing brand named after the abbey
• List of Carolingian monasteries
• Manoir de Brion
• Monemvasia
• Mont-Saint-Michel Abbey
• Mont Saint Michel and Chartres (1904) by Henry Adams
• Saint-Malo
• Saint Michael in the Catholic Church
• St Michael's Mount, Cornwall

• Mont Saint-Michel：A World Heritage Site
• Freeing Mont Saint-Michel
• Mont-Saint-Michel Celebrates 1,300 yrs of History
• Mont Saint-Michel between history and legends
• Official Mont-Saint-Michel Tourist site (English version). Archived 16 June 2019 at the Wayback Machine
• Virtual recreation of Mont St. Michel in Second Life
• Pano at 360° of Mont St Michel
• High-resolution 360° Panoramas and Images of Mont Saint-Michel | Art Atlas. Archived 12 September 2019 at the Wayback Machine
• The Sledge Tramway