Rock Harbor Lighthouse Seeing The Light

Off Isle Royale, Lake Superior, Michigan Home Back

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Historical Information

Isle Royale lies out in Lake Superior some sixty miles to the north of the Keweenaw peninsula, and a scant 14 miles south of the Canadian north shore. It would be natural to assume that an island located so close to the Canadian shore would be Canadian territory. However, during border negotiations between the British and the nascent United States at the Treaty of Paris in 1783, misunderstandings resulting from a lack of accurate maps of the area caused the island to be included as part of United States territory. While a number of Scandinavian fishermen would set up operations on the island in the early 1800's, and John Jacob Astor's American Fur Company would establish a trading post here in 1837, it would not be until the late 1840's that the United States government would realize the windfall that resulted from the 1783 cartographic misunderstanding.

After the signing of the treaty of LaPointe with the Chippewa Nation in 1843, Isle Royale was opened to mineral exploration, and by 1847 more than a dozen mining companies were working the island. Of these, the two largest were located in Siskiwit Bay on the southeastern end of the island and at Rock Harbor to the north. Thriving towns in the area around the mines to support the needs of both mine and miner, and an increasing number of vessels began arriving to deliver supplies and transport copper to the hungry industrial centers on the southern lakes. With Congressional approval of the new lock at the Sault granted in 1852, expectations of boom times on Superior were high, and with this boom, maritime traffic in the Isle Royale area was expected to grow exponentially.

In his annual report to the Fifth Auditor of the Treasury for 1852, Henry B Miller the Superintendent of lights on the upper lakes recommended that $5,000 be appropriated for the establishment of a lighthouse at the entrance to Rock Harbor, to serve as a guide to mariners seeking to enter that harbor. Congress responded with the requested appropriation on appropriated on March 3, 1853. That same summer, a survey crew arrived at Rock Harbor and selected a site for the new Light, and the process of obtaining title to the property was begun. With title negotiations coming to completion at the end of the year, plans were formulated to commence construction with the opening of the 1854 navigation season.

Click to view enlarged imageConstruction appears to have began the following year, but for as yet undetermined reasons was not completed until 1856. The station's rubble stone tower stood 16 feet 11 inches in diameter at the foundation, with its 49 foot 11 inch high walls tapering gently to a diameter of 14 feet 1 inch below the circular gallery. A set of spiral pine stairs supported by a central pine post wound within the tower from the first floor to a trap door in the gallery floor to provide access to the lamp. The lantern itself was fabricated of cast iron, and featured a domed copper roof. Centered within the lantern, a fixed white Fourth Order Fresnel lens sat at a focal plane of 70 feet above lake level, and cast its light 15 miles across the lake The attached rubble stone dwelling, stood 29 feet square and 20 feet 9 inches high at the apex of the cedar shingled roof.

Click to view enlarged imageMark Petty was appointed as the station's first Keeper and with his brother Michael as his Assistant, both arrived at the station on October 24, 1856, and exhibited the light for the first time soon thereafter. After a short year at the station, Michael passed away on July 16, 1857 and with his brother's death, Mark resigned from lighthouse service. The Petty's were replaced by a second pair of brothers when Francis and William Bomassa were assigned to the station. Evidently William was ill-suited for the rigors of lighthouse keeping on such a remote location, as he resigned his position on September 8, 1858, leaving alone to tend the light.

With the closure of the mines and dwindling maritime traffic in the area, the Lighthouse Board determined that the Rock Harbor Light no longer served any real purpose as a navigational aid, and the decision was made to abandon the station. After extinguishing the light and locking the station doors, Francis Bomassa followed in his brother's footsteps, boarded a boat, and bade farewell to both the light and to lighthouse service on August 1, 1859, leaving the Rock Harbor light alone to face the ravages of time and the elements.

Click to view enlarged imageWith the outbreak of the Civil War, and a resulting increase in metals consumption, miners once again set their sights on Isle Royale, and new and more efficient mines were established at Siskiwit Bay on the southeast shore and McCargo Cove on the northwest. Once again, thriving communities grew up around the mines to support the mining and shipment of copper, and with a resurgence in maritime traffic making for the island to transport copper south through the Sault Locks, the Eleventh District office began to consider reactivating the old Rock Harbor Light.

Click to view enlarged imageA complete examination of the abandoned station was undertaken in 1873, and plans put in place for its renovation and reactivation at a total cost of $5,000. A work party and materials were delivered at Rock Harbor in late June of 1874 and a number of improvements undertaken. The entire building given a cement wash coat, interior walls were re-plastered, buckled pine flooring was replaced and the roof re-shingled. A new woodshed, boat house and dock were also built, and with a change in the characteristic of the light from fixed white to fixed red, the work came to an end. Acting Keeper Anthony Kruger reported to take charge of his "new" station, and after moving into the renovated dwelling, Kruger ascended the pine stairs in the tower to reactivated the station's Fourth Order Fresnel for the first time on the evening on August 5. Kruger would tend the light alone for over a year before Acting Assistant Ferdinand Dumont was appointed to the position and arrived at the station on October 23, 1875.

Click to view enlarged imageIn a fateful repetition of history, copper prices again plummeted with the end of the Civil War, and Isle Royale's second mining boom came to a close. With the establishment of the new Isle Royale Light on Menagerie Island on October 19, 1875, the Rock Harbor Light's days were again numbered. Four years later, Keeper Martin R Benson exhibited the Rock Harbor light for the last time on October 4, 1879, and left the island for his new assignment as Keeper of the Portage Lake Ship Canal light.

Click to view enlarged imageOther than being used as a base of operations for a couple of fishermen working off the island in the 1930's when two dormers were added to the roof and the lean-to at the rear of the dwelling was enlarged, the old station sat empty, and slowly deteriorating. With then establishment of the Isle Royale National Park in 1939, the old structure became a part of the National Park, however serving little purpose to campers or the Park system, no steps were taken toward either rehabilitation or restoration. In the late 1950's the tower began to tilt, and fearing that the tower might topple, an emergency stabilization was undertaken, limiting the lean to approximately two degrees from the vertical.

An improved trail system throughout the island has now made the lighthouse easily accessible, and many hikers now take the time to visit the venerable station.

Keepers of this Light

Click here to see a complete listing of all Menagerie Island Light keepers compiled by Phyllis L. Tag of Great Lakes Lighthouse Research.

Finding this Light


The Isle Royale National Park conducts a number of Ranger-led interpretive hiking tours of Isle Royale historic sites. One such tour out of Rock Harbor covers both the the Edisen Fishery and Rock Harbor Lighthouse. This tour lasts approximately 4 hours, and departs from Rock Harbor at 2.00 PM on Thursdays and at 9.00 AM on Saturdays e tours throughout the summer season. For additional information, click here to visit the interpretive programs section of the NPS Isle Royale website.

Keweenaw Excursions also offers a lighthouse cruise which passes Rock Harbor on board the KEWEENAW STAR out of Houghton, Michigan. For more information on any of their tours visit their website, or telephone Keweenaw Excursions at (906) 482-0884.

Reference Sources


Isle Royale National Park, foot trails & water routes, Kim DuFresne, 1984
Annual reports of the Lighthouse Board, various, 1878 - 1909
Annual report of the Lake Carrier's Association, 1915
Log books of the Menagerie Island Light, transcribed by Don Nelson.
Northern Lights, Charles K. Hyde
Email correspondence with Don Nelson, various, 2002
Photographs of the station taken in 1991 courtesy of Don Nelson
Photographs of the station taken in 2000 courtesy of Wayne Sapulski
Keeper listings for this light appear courtesy of Great Lakes Lighthouse Research


This page last modified 12/02/2007

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