Cap Gris-Nez is a prominent cape located in Audinghen, a commune in the Pas-de-Calais département of northern France. Part of the Côte d'Opale, it is classified as a protected natural area. Its cliffs mark the closest point of France to England, separated by just 34 kilometers (21 miles).

The name "Gris-Nez" translates to "grey nose" in French, referencing the gray-colored cliffs of the cape. The Dutch name, "Swartenesse" ("black cape"), distinguished it from "Blankenesse" ("white cape"), now known as Cap Blanc-Nez to the northeast. The suffix "-nesse" or "-nez" is cognate with the English "-ness," signifying a headland, as seen in Dungeness and Sheerness.

The cliffs of Cap Gris-Nez are composed of sandstone, clay, and chalk, primarily gray in color. The area is a renowned site for fossil hunting, with most fossils originating from the Jurassic period. These include bivalves, gastropods, and fossilized wood. Rare finds, such as large ammonites, as well as fish and reptile teeth, are occasionally uncovered in the sandstone layers containing small pebbles.

The cape is a migration bottleneck, making it a popular strategic spot for birdwatching and surveying. It offers a well-known vantage point for viewing both birds migrating across the Channel, and birds migrating along the coastline.

The proximity of the cape to England resulted in the frequent destruction of the nearby village of Audinghen in wars between England and France. On the top of the cliff are the ruins of an English fortress, built by Henry VIII at the beginning of the 16th century. The English called the fort 'Blackness', a translation of the Dutch name Swartenisse.

Napoleon stopped at the cape on July 1, 1803, while inspecting the coast around Boulogne-sur-Mer with his invasion troops. He envisioned setting up a cross-channel optical telegraph with a semaphore on the cape. The first semaphore of this line was installed on the cape in 1805 without waiting for the planned French invasion of England.

On July 18, 1805, the Battle of Gris-Nez and Blanc-Nez occurred, wherein a British flotilla with strong numerical superiority pursued Dutch ships that were following the coast while trying to get into the harbour at Ambleteuse. Expecting an attack of this type, Napoleon had stationed a battery of 300 guns on the cape, and a barrage from this force obliged the British vessels to withdraw.

Gabriel Auguste Ferdinand Ducuing and his men died on May 25, 1940, while defending the semaphore, and a commemorative stela was later placed on the cape to commemorate this sacrifice.

Later, the Nazis built a blockhouse inside the Tudor ruins. The locality has a cluster of World War II bunkers, part of the Atlantic Wall intended to rebuff the anticipated allied invasion. There are two heavy artillery sites: Grosser Kurfürst Battery, formerly with three 170 millimetre guns, and Todt Battery, with four 380 mm guns. These covered the approaches to both Calais and Boulogne, and they were protected by large concrete blockhouses as well as other lesser defensive sites. One of the Todt Battery blockhouses now houses the Atlantic Wall Museum.

Units of the 3rd Canadian Infantry Division liberated the area in September 1944.

The current cylindrical concrete lighthouse at Cap Gris-Nez, built in 1958, replaced a previous structure destroyed during the war. Standing 31 meters (102 feet) tall, it provides critical guidance alongside a radar station for over 500 ships passing daily through this heavily trafficked maritime route.

The lighthouse and its accompanying radar station provide guidance to over 500 ships passing the cape every day.

• Itius Portus
• Cross-Channel guns in the Second World War

50°52′15″N 1°35′01″E / 50.87083°N 1.58361°E / 50.87083; 1.58361