Benjamin Cowan was born between 1834 and 1838, probably in Salem, Maine, the son of James Cowan and Lucrecia Winslow.
According to a descendant, Benjamin Cowan's great grandfather Thomas Cowan arrived in America with a group of Scottish Presbyterians from northern Ireland, led by a minister named James McGregor. Research shows that this migration was in 1718, from Aghadowey, Derry/Londonderry County.
I have looked through the Session Book for the Presbyterian Church, Aghadowey, Co. Londonderry, Ireland, 1702-1725, in the R. Stanton Avery Special Collections Department, New England Historic Genealogical Society (Boston, Mass.), Mss 439. A "Granny o Cohan" and a "Noaly/Nealy o Cohan" are listed as receiving aid from the church.
This area might be a good place to look for the Cowans' Irish place of origin.
Benjamin's mother Lucretia Winslow might be the daughter of Kenelm Winslow and Elizabeth Cole; The Coles were from Plymouth Colony. There were a Kenelm and Edward Winslow in Plymouth as well, one of whom may be the immigrant ancestor for the Maine branch. Edward Winslow was a 1620 Mayflower passenger, Kenelm Winslow and the Coles were not.
The paternal ancestry of Benjamin's paternal grandmother, Susannah Kilbourne goes back to Rowley and Salem, Massachusetts. It includes Mary Jackson, the sister of Elizabeth (Jackson) Howe, executed in Salem on 19 Jul 1692 during the witch trials.
Susanah Kilbourne's mother was Susanna Fiske. The Fiske family have been traced back to a Richard Fiske, born about 1493 in Laxfield, Suffolk, England. They had ben in Suffolk from at least 1208.
correspondence with descendants
US Federal Censuses
Maine Vital Records, 1892 to 1955, microfilm at New England Historic and Genealogical Society
Marriage Returns of Penobscot County, Maine prior to 1892, Ruth Gray, editor, (Camden, Maine: Picton Press, 1994),
Maine Families in 1790, Rockport, ME: Picton Press
Their source was Hallowell Vital Records.
Their source: Dunstable Vital Records.
Early Settlers of Rowley, Massachusetts, George B. Blodgette
Rowley Vital Records
International Genealogical Index, extracted record, at: familysearch.org