The Redoubt

Redoubt wayside

2nd. Lt. Henry M. Robert of the U.S. Army Engineers explains to sergeants his plan for the earthen fortification (or redoubt) on San Juan Island's southern peninsula. The redoubt sent a clear signal to the British that the Americans intended to remain on the island.

NPS Art Collection


In mid-August 1859, a growing contingent of U.S. Army troops on San Juan Island was confronted by three British warships mounting 70 guns. The Americans had lugged ashore eight naval guns from the USS Massachusetts, and had several field pieces at their disposal.

But as local commander, Lt. Col. Silas Casey reported, “...With our present appliances I find them rather difficult to manage.” Getting on in years and deeply religious, Casey was horrified by the prospect of open hostilities with the British. He was well aware of the power of the Royal Navy.

“It is not pleasant to be at the mercy of any one who is liable at any moment to become your open enemy,” he wrote Department of Oregon commander, Brig. Gen. William Selby Harney in requesting help with the guns.

Casey’s forces had been dispatched to the island by Harney to protect United States citizens from the British, who Harney believed were claiming sovereign jurisdiction over a disputed territory. The long-festering issue had flared into armed confrontation in June when an American settler had shot a pig belonging to the Hudson’s Bay Company. The company wanted fair restitution. The settler thought they wanted to jail him. Everyone overreacted — most especially Harney.

Illustration of earthwork with guns.

The redoubt was designed to function much as the example above. It was the unloading of the scantlings for gun platforms that alarmed British commanders.

NPS Illustration

The general took Casey at his word and on August 16 dispatched to San Juan Island a 10-man detachment (called a sapper team) of Company A, U.S. Army Corps of Engineers, commanded by 2nd. Lt. Henry Martyn Robert. Robert was to report to Casey, who would place him in charge of creating a fortification for the naval guns, as per Harney’s instructions, which had been relayed by the department’s acting Adjutant General, Capt. Alfred Pleasanton (later to achieve fame as a Union cavalry officer in the Civil War). “...Have platforms made for your heavy guns, and cover your camp as much as possible by entrenchment, placing your heavy guns in battery on the most exposed your position with the greatest care to avoid fire from the British ship(s).”

Casey already had taken delivery of large quantities of lumber “fit for gun platforms,” which the British Capt. Geoffrey Phipps Hornby, RN, noted was being stockpiled on the beach. Hornby commanded the 31-gun steam frigate HMS Tribune, anchored in Griffin Bay for nearly two weeks. The naval guns had been wrestled into place on the ridge overlooking Griffin Bay, while the camp had been moved from the exposed prairie above South Beach to just north of the Hudson’s Bay Company farm.

prairie from redoubt

The redoubt would have a commanding view of San Juan Island's southern tip and the water approaches to the prairie from Griffin bay (left) and the Strait of Juan de Fuca.

NPS Photo

Geoffrey Phipps Hornby, RN

Capt. Geoffrey Phipps Hornby, RN, was so alarmed at the sight of the the redoubt exacvation that he asked permission to storm the heights and spike the U.S. guns.

Image Courtesy of William J. Schultz, MD

Capt. James Prevost, RN, commander of HMS Satellite, reported that the new camp “is very strongly placed in the most commanding position on this end of the island, well sheltered in the rear and on one side by the Forest, and on the other side by a Commanding eminence.”

Casey said “...I shall put my heavy guns in position to bear upon the harbor, and also on vessels which might take a position on the other side. Shells from shipping may be able to reach us, and we may not be able to protect the camp from them; but I shall try.” The sight of these preliminary works alarmed Hornby enough to dash off a dispatch to his superior, Rear Adm. R. Lambert Baynes, RN, commander of the British Pacific Station squadron based in Victoria.

“Six of their heavy guns are placed on the ridge of the hill overlooking the harbour; and by throwing up a parapet they would command the harbour; even in their present position they would be difficult to silence,” Hornby wrote. As the son of an Admiral-of-the-Fleet and an experienced 19th-century military man in his own right, Hornby recognized how construction of a formal field work could alter the situation on San Juan Island. He knew that a fortress not only provided a means of last ditch defense, but sited in a strategically dominant position, would permit a smaller force -- even with inferior troops -- to resist a larger one long enough for more substantial resistance to be mounted. Once dug in, the Americans might never be uprooted and the island would be lost, politically as well as militarily.

Satellite from aft

The redoubt was to be armed with naval guns slightly smaller than those shown above on HMS Satellite, a 21-gun steam corvette anchored in Griffin Bay throughout the crisis. The range of the guns was about a mile and half, enough to send plunging fire on the British ships.

Yale Collection of Western Americana, Beinecke Rare Book and Manuscript Library, Yale University


Robert and his crew landed on August 21 and almost immediately went to work, supplemented by details from Casey’s infantry and artillery companies. According to the diary of William A. Peck, Jr., one of Robert’s soldiers, the fort was “laid out of an irregular form 425 feet long above the natural ground; ditch 20 feet wide, not less than 8 feet deep.”

Peck wrote that the earthwork had been altered two days later, but gave no new dimensions. When the historian Hubert Howe Bancroft visited the site in 1887, he measured the work and jotted down essentially the same dimensions as today: 350 feet on the west side, 100 on the southeast and 150 on the northeast. Five gun platforms were completed, two of them at the corners, with the parapet seven feet above the interior, the exterior 25 to 40 feet, and ditch at the bottom from three to five feet across. Robert, an 1857 graduate of West Point, built the work based on knowledge gleaned during his studies at the academy under Professor Denis Hart Mahan. Mahan had first published a book on the subject in 1836 and had updated it over the years. The cadet curriculum also included hands-on construction of model and full-sized fortifications.

From the observations of British officers and members of the press from Victoria and San Francisco, Robert followed the standard dictums: selecting his ground to the best advantage, leveling the ground, and setting poles, which would guide uniformity in establishing the height and breadth of the ramparts (or walls).


The redoubt's features-ramparts, ditch and glacis (or approach)- are still readily identifiable on the skyline from the prairie below.

NPS Photo


As Captain Prevost reported, “...the hill south of the American Camp, has been marked out for fortifying, in several places it has been leveled, and working parties have lately been employed in throwing up earthworks.” The British Colonist estimated that at least 100 men were designated for the task, including one British subject who had been apprehended for liquor selling. It all was done with pick and shovel, which presented a challenge for the men, who had to clear enormous rocks left in the wake of glaciers that had receded thousands of years before.

For all this back-breaking labor, the redoubt never fired a shot in anger. In fact, only three guns were ever emplaced and these merely fired a salute to Lieutenant General Winfield Scott when he visited Griffin Bay on November 7, 1859. The general had ordered work on the fortress stopped after he and British Columbia Governor James Douglas agreed to reduce their forces on the island.

In ensuing years, the work became known as “Robert’s Gopher Hole.” Nevertheless, as an instrument of policy -- however misguided that policy may have been -- the redoubt had done its work. It had served notice that the Americans intended to remain and spurred the British to time and again reevaluate their options during the crisis.


The redoubt was the scene in 1904 of the dedication of the former U.S. Army camp site as a monument to the peaceful resolution of the boundary dispute. The stone cenotaph erected that day has since been moved to the parking area of the American Camp visitor center.

Washington State Archives


The redoubt today is protected as a historical structure of national significance. It also offers one of the most spectacular near sea level view sheds in the National Park Service.

NPS Photo

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