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Minots Ledge Light Station


Lighthouse Data

Established: Jan 1, 1850
Rebuilt: Aug 22, 1860
Light List: Aid No. 440/J0360
Position: N 42° 16' 12", W 70° 45' 32"
Nautical Chart
Cohasset Rocks,
outside Boston Harbor,
Offshore from Scituate and
Cohasset, Massachusetts
Characteristic: Fl (1+4+3) W 45s (2)
[Flashing White (1-4-3)
every 45 seconds
Original Optics: Second-order Fresnel Lens
Present optic: 300 mm Lens (solar powered) - 1983
Elevation: 85-feet high Focal Plane
Range: 10 nautical miles visible reach at sea
97-feet high Conical Natural Granite
Tower with Copper Lantern
Fog signal: One 1-sec Blast every 10 seconds
First Keeper: Isaac Dunham (3)
Automated: 1947
Current Use: Active aid to navigation,
U.S. Coast Guard

(1) The most “Wave-Swept” Lighthouse was built to mark dangerous submerged Cohasset Rocks off the coast of Cohasset six miles southeast of Boston Harbor. Minots Ledge is also called “the most dangerous beacon in America” because the Lighthouse was built on a hazardous submerged rock about 25-feet wide that is only exposed 2 to 3 hours every day at low tide.

      Even though Boston Harbor Lighthouse was established in 1716 for the safety of commerce entering the harbor, there were numerous shipwrecks caused by a treacherous submerged group of ledges, Cohasset Rocks, north of Cohasset Harbor and south of Boston Harbor.  During the ‘Age of Sail,’ coastal trading shipping lanes were within 3-miles offshore since coasters navigated by sighting coastal land features and Lighthouses.  Minots Ledge, 1-mile offshore from Strawberry Point, was a hazardous obstruction barely visible at low tide.

      In 1843, I.W.P. Lewis, Civil Engineer to the U.S. Light-house Survey, reported 40 shipwrecks occurred on Minots Ledge located 8-miles Southeast of Boston Light from 1832 to 1841.  He recommended a Lighthouse was more required on the reef “than on any part of the seaboard of New England” to Stephen Pleasonton, Fifth Auditor of the Treasury Department.  Upon reviewing the property damage of $364,000, Pleasonton approved building a Lighthouse.

      The design of the Lighthouse required four years due in part over the debate of whether a granite Tower or iron-pile Lighthouse was capable of withstanding the forces of the open ocean.  Pleasonton approved the iron-pile design of Captain William H. Swift, U.S. Topographical Department, who believed a spider-like iron pile structure drilled into the rock would allow water to freely flow around the legs in order to protect the Lighthouse.

      From 1847 to 1850, nine holes were drilled 5-feet deep in the ledge at low tide to cement eight exterior 10-inch diameter iron piles and one center pile for supporting a Lighthouse 75-feet above sea level.  A 5-ton cast-iron spider secured the top of the piling.  The Lighthouse was constructed with three levels: a storage room on level one, living quarters for the Lightkeepers on level two, and the Lantern Room on top.  Minots Ledge Light was First Lit on January 1, 1850 by Lightkeeper Isaac Dunham exhibiting a Fixed White light illuminated by 15 oil lamps and reflectors.

      After nine months of living in the unstable Lighthouse, Keeper Dunham resigned after no action was taken to reinforce the Tower (see Note 3).  Captain John W. Bennett was appointed as the second Lightkeeper and he employed two assistant Keepers, Joseph Wilson and Joseph Antoine since two Keepers were needed to rotate night watches at the Light.  Horizontal bracing of the structure was frequently removed to be straightened and strengthened due to powerful forces of the waves that caused the Lighthouse to sway two feet.  Storm forces increased the instability of the structure instilling apprehension in the Lightkeepers for their lives.

      On April 17, 1851, the Lighthouse was destroyed by a severe storm that caused coastal flooding and damage.  The storm weaken the support piles until they collapsed where horizontal iron rod braces were omitted at the base of the Tower.  The two assistant Keepers managed to keep the lamps burning and the Fog Bell was last heard about 1 am.  Joseph Wilson died of exposure at Gull Rock and Joseph Antoine’s body was discovered on the shore of Nantasket.

      From 1851 to 1860, Scituate Light was reactivated and two Lightships were placed On Station at Minots Ledge: Old Brandywine Shoal Lightship exhibited a Fixed White light on the foremast and the mainmast from 1851 to 1854; and Light Vessel LV7, “Minots Ledge Lightship,” exhibited 2 Fixed White lights illuminated by 8 oil lamps with 12-inch reflectors from 1854 to 1860.

      From 1851 to 1855, General Joseph G. Totten of the Lighthouse Board, designed the new Minots Ledge Light based upon the interlocking masonry plans of the fourth Eddystone Lighthouse* designed by John Smeaton, “the Father of Civil Engineering.”  General Totten planned a “Sea Rock Light,” a conical Tower constructed of large interlocking dovetailed granite blocks that would withstand the forces of the open sea.

      On June 20, 1855, Barton Alexander, U.S. Corps of Engineers, began supervising the work on the new Minots Ledge Light at Government Island connected to the mainland in Cohasset where the granite stone was cut and preassembled.  The granite blocks were transported 2.5-miles to the ledge on calm days and the foundation and base of the Tower were constructed when the ledge was exposed at low tide.

      The work at the ledge was dangerous, tedious, and waves frequently swept workers off the reef.  Storms and winter also delayed construction.  The final stone was laid on June 29, 1860 to complete the construction of the Tower.  The new tower was built using 1,079 Quincy granite blocks dovetailed and reinforced with iron bars at a cost of $330,000.  A Lantern Room and Second-order Fresnel lens was installed and the Lighthouse was temporarily illuminated on August 22, 1860.

      Minots Ledge Light was not regularly exhibited until November 15, 1860 when Joshua Wilder, the new Lightkeeper, and his two assistants began tending the Lighthouse.  A fresh water cistern is located in the center of tower with five levels above for Keeper’s quarters, assistant Keeper’s quarters, oil storage, kitchen and living quarters.  A watchroom and the Lantern Room caps the 97-feet high Lighthouse which has withstood the forces of the sea and storms for the past 142 years.

      Five months after the new Lighthouse was first lit, Fitz James O’Brien’s “Minot’s Ledge” poem was published in Harper’s New Monthly Magazine.

      On May 1, 1894, the Lighthouse was refitted with a revolving optic with a Characteristic of 1-4-3 flashing sequence and romantic lovers on the shore discovered the grouping was the same numerical count as the words “I love you.”  Minots Ledge Light was soon known as the “I Love You Light” or the “Lover’s Light.”

      In 1947, the Lighthouse was automated and the Third-order Fresnel lens was replaced by a electric optic.  The Fresnel lens was stored in a bedroom below and later, vandals damaged and destroyed sections of the lens. The repaired Fresnel lens can be viewed at Government Island (see Note 4).

      In 1983, the optic was refitted with a ML300 lantern powered by six 12-volt batteries charged by four solar panels.  The Lantern Room was removed and the Tower renovated from 1987 to 1988.  The Cohasset Historical Commission used some of the original granite blocks that were removed in 1988 for the construction of Lantern Room Replica on Government Island.

*The fourth Eddystone Lighthouse was built on Eddystone reef, 14-miles offshore in the open sea of the English Channel near Plymouth Hoe, England and was First Lit on October 16, 1759 illuminated by 24 candles.

(2) The distinctive Light Characteristic, 1-4-3 flashing sequence, has same numerical count as the words “I love you.”  Minots Ledge Light was soon nicknamed the “Lover's Light” or the “I Love You Light.”

The full Flash sequence is: 1.5s Flash, 5s Eclipse; 1.5s Flash, 1.5s Ecl ; 1.5s Flash, 1.5s Ecl ; 1.5s Flash, 1.5s Ecl; 1.5s Flash, 5s Ecl; 1.5s Flash, 1.5s Eclipse ; 1.5s Flash, 1.5s Eclipse ; 1.5s Flash, 15.5s Eclipse

(3) Keeper Isaac Dunham resigned on Oct 7, 1850 after surviving several severe storms because he felt the Tower was structurally unsound.  The second Keeper, former sea captain John Bennett, agreed with the Designer Captain William H. Swift on the safety on his Tower.  However, a Northeast Storm in the Fall of 1850 changed Keeper Bennett’s mind about the Towers’ safety.

      Apr 8 - 17, 1851: A severe Storm battered the Lighthouse with powerful winds and waves straining and weakening the support piles until the Tower was destroyed on April 17.  Both Keeper Bennett’s assistants, Joseph Antoine and Joseph Wilson, lost their lives sometime after 1 am when the Fog Bell was sounded for the last time.  On May 21, 2000, a Memorial Monument was dedicated in tribute to two lighthouse keepers who lost their lives to the sea.

(4) The Original Third-order Fresnel Lens, the Original Fog Bell, and a Replica of Minots Ledge Light’s Lantern Room is located on Government Island, Cohasset, Massachusetts where 1,079 Granite Blocks were hewn and preassembled before raising the Lighthouse on the ledge.

      The Following Light Data describes the Lighthouse at the turn of the century (1900):
N 42° 14' 20"; W 70° 47' 20"
Public Access:


Original optic:


Tower Height:


Fog signal:
   Grounds Only at Government Island

Fl (1+4+3) W 30s [Flashing White (1-4-3) every 30s]
May 1, 1894 (1 flash, eclipse 3 secs; 4 flashes, eclipse
3 secs; 3 flashes, eclipse 15 secs.)

Third-order Fresnel lens

Conical Natural Granite Tower with Copper
Lantern Room

89 feet;   Height of focal plane: 85 feet;

15 miles

Bell struck by machinery every 30 seconds

Lantern Replica

Directions from Boston to Government Island:
Take MA-3 South to Exit 14 (Hull, Nantasket, Rockland) and turn Left onto MA-228 North (about 7-mi).  At the junction of MA-228 and MA-3A, continue straight onto East Street (.5-mi).  East Street becomes North Main Street (2.19-mi).  Turn slight Left onto Elm Street (.33-mi) and turn slight Right onto Border Street. Drive over the bridge and take the next left onto Government Island.  There is an ample free parking area.  The Maritime Museum has exhibits and the story of Minots Ledge Light:

Right ArrowGovernment Island Map

Cohasset Historical Society’s Maritime Museum
4 Elm Street
eMail: tlg@dreamcom.net
For Information, call (781) 383-1434
From June to Sept, 1:30 to 4:30pm Tuesday to Sunday

(5) One of the top ten Engineering Feats of American Lighthouse Stations due to the precision of Construction and planning. For example, the force of powerful waves strengthen the Tower because the granite blocks are dovetailed and interlocked.

(6) Minots Ledge Light is best viewed from the water by either a private boat or a Lighthouse cruise:

      Boston Harbor Explorers schedule six-hour Lighthouse cruises from Boston Harbor to the North Shore and South Shore.  For information, call (617) 479-1871.

Friends of the Boston Harbor Islands
(781) 740-4290
The Friends generally schedule Southern Lights Cruises that pass Minots Ledge Light
yet the cruise is entitled the Plymouth Expedition this year.

      There are several vantage points along the coastline for distant views of the Lighthouse:
Traveling from North to South,
A) From MA-228 in Hull, Atlantic Avenue and Jerusalem Road is one of the best scenic coastal drives in New England.

B) Sandy Beach, Atlantic Avenue, is a rocky coastline with parking for Cohasset residents only.  Minots Ledge Light can be seen as you drive by the beach.

C) and Minot Beach, Glades Road, Cohasset.

Home Next

Public Access

No Access,
Best Viewed by boat;
Distant views from Atlantic
Ave, Cohasset. (6)

Cohasset Harbor

- Google Map 

Link to a Map of Government
Island, Cohasset, where the
Replica of Minots Ledge
Light’s Lantern Room is
located. (4)

Travel Links

Lighthouse Cruises

- Friends of the
 Boston Harbor

Plymouth Lighthouse
is a Special
Lighthouse Cruise
scheduled annually

Minots Ledge


Existing 1858 Keeper’s
house, assistant Keeper’s
house and oil house
Located on Government
Island, Cohasset - (4)

American Society of Civil
Engineering Landmark (5)

National Register of Historic
Places -19870615
Lighthouses of Massachusetts
TR 87001489

Document Updated: Thu 16 Sep 2010, 5:07:00pm EDT (GMT-4)

Copyright © 2000 to 2010 by Debbie Dolphin. All Rights Reserved.

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