Sylvanus A. Denio

Quick Facts

Significance:

Businessman, machinist, member of the 1850 Boston Vigilance Committee

Place of Birth:

Bakersfield, Vermont

Date of Birth:

June 1, 1818

Place of Death:

Boston, Massachusetts

Date of Death:

March 28, 1892

Place of Burial:

Cambridge, Massachusetts

Cemetery Name:

Mount Auburn Cemetery

Boston businessman Sylvanus A. Denio served on the 1850 Boston Vigilance Committee, an organization that assisted freedom seekers on the Underground Railroad.

Born on June 1, 1818 in Bakersfield, Vermont, Sylvanus A. Denio moved to Boston as an 18-year-old. He first worked at the blacksmith shop of Whittredge and Adams, at the corner of Causeway and Friend Streets. He eventually became partner with them, and upon their death, established his own ironworks and machinist firm with his partner Charles Roberts. They manufactured architectural iron and safes, building the first safety deposit vaults in Boston. Denio and Roberts often contracted with the government, including the Treasury Department in Washington, D.C. They also furnished jails with their iron work in other contracts with counties across the state of Massachusetts.¹

While running his successful business in Boston, Denio also became involved in the local antislavery movement. Following the passage of the Fugitive Slave Law in 1850, he joined the Boston Vigilance Committee. The Vigilance Committee provided funds, shelter, transportation, medical attention, and other assistance to freedom seekers escaping enslavement on the Underground Railroad. Although Denio’s name and address appeared on the official broadside published by the Vigilance Committee, his contributions to the organization remain unknown.²

In addition to his antislavery work, Denio participated in local politics and charitable organizations. He successfully ran for office in the city as a member of the Republican and Citizen’s Party in the 1860s. He served on the Common Council in 1861 and as an Alderman from 1863 through 1865. Denio also held several leadership positions in the Massachusetts Charitable Mechanics Association.³

Sylvanus A. Denio passed away at age 73 on March 28, 1892, from chronic myelitis and pneumonia. One obituary stated that he left a “legacy of a spotless reputation and an unsullied name.” In his will, he also left a significant sum of his money—fifty thousand dollars—to the Museum of Fine Arts in Boston. Today, impressionist and modern art collections are held in his name at the museum.⁴

His remains are buried in Mount Auburn Cemetery in Cambridge, Massachusetts.⁵

If you are a researcher or descendent of Sylvanus A. Denio or can provide any further details of his work in the Vigilance Committee or larger antislavery movement, please e-mail us.

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Footnotes

1. National Park Service maps Denio at his business address at the corner of Causeway and Friend Streets. Boston Evening Transcript, March 29, 1892, 10. “Obituary,” Boston Journal, March 29, 1892, 2; Stimpson’s Boston Directory, 1837,(Boston: Stimpson and Clapp, 1837), 396, Stimpson's Boston directory. [1837] : Free Download, Borrow, and Streaming : Internet Archive
2. "Members of the Committee of Vigilance," broadside printed by John Wilson, 1850, Massachusetts Historical Society, Austin Bearse, Reminisces of the Fugitive Slave Law Days (Warren Richardson, 1880), 3, Internet Archive.
3. Boston Evening Transcript, December 9, 1862, 4; Municipal Register: Containing the City Charter, the Rules and Orders of the City Council, and a List of Officers of the City of Boston for the Year 1868, (Boston: Alfred Mudge and Son, 1868), https://archive.org/details/municipalregist00masgoog/page/n10/mode/2up
4. Ancestry.com. Massachusetts, U.S., Death Records, 1841-1915 [database on-line]. Provo, UT, USA: Ancestry.com Operations, Inc., 2013.; The Cass County News, February 15, 1895.; A Tribute to Sylvanus A. Denio,” Boston Evening Transcript, April 1, 1892, 1
5. “Sylvanus A Denio,” Find a Grave, Sylvanus A Denio (1818-1892) - Find a Grave Memorial