Keep Calm and Carrigan On: Using Collateral Research to Find Irish Ancestors

By Andrew Koch

Collateral research—studying the siblings and cousins of your ancestors—can help you overcome some of the hardest genealogy roadblocks. In this case study from Claire Santry’s new book The Family Tree Irish Genealogy Guide, Editor and Content Producer Andrew Koch uses collateral research to discover his Irish immigrant ancestors in records from the Emerald Isle:

I’ve always been enchanted by Irish culture: the lyrical names (Saoirse, Liam, Siobhan), the beauty of a well-played fiddle, the vibrance of St. Patrick’s Day. Despite my decidedly German last name, I always hoped I had some Irish blood in me.

Sure enough, tracing census returns back generations revealed my great-great-great-grandfather, James Carrigan. Carrigan! An Irish name if I’ve ever heard one. Kiss me, I’m 1/32 Irish!

So what could I learn about the Carrigan line and where it came from? I started by researching James in US sources. From census records, online cemetery indexes, an Ohio death index, James’ declaration of intention, a New York passenger list and a Social Security death index entry for his daughter (my great-great-grandmother), I learned that James (born in Ireland about 1856) married, had his first son in England, and immigrated to the United States all in the same year: 1880.

His English-born wife, Rose Flynn, and infant son, James Thomas, joined him in Cincinnati within the next couple years. The couple had six more children (including my ancestor, Mayme) before Rose died in 1899 and James in 1914.

This was a great start, but I still had unanswered questions: Where in Ireland was James from, and what were his parents’ names? A distant relative on told me that James and his ancestors came from Dublin, but she didn’t have concrete proof. She did, however, have James and Rose’s marriage certificate and James Thomas’ birth certificate. The documents revealed that James Thomas was born less than nine months after his parents’ wedding (oops!). But the only other new information was the name of James’ father: Patrick.


Likewise, my own research in Irish records was mostly fruitless. Civil registration didn’t begin until a few years after James’ birth, and I couldn’t definitively find parish records with a potential hometown as broad as “Dublin.” With help from Claire Santry (the author of The Family Tree Irish Genealogy Guide), I had a lead—a clump of baptism records for “Corrigans” in St. Andrew’s parish in Dublin. Each Corrigan had a Patrick and a Catherine as parents, and I also found entries for a James, baptized in 1854 (relatively close to my James), and a Mary, baptized in 1853. But without more proof, I couldn’t draw any conclusions.

Remembering the principle of collateral research, I knew it was time to search more broadly. I started researching James and Rose’s six children who weren’t my direct-line ancestors: James Thomas (b. 1880), Patrick (b. 1882), William (b. 1886), Thomas (b. 1888), Rose Ann (b. 1889), and Catharine (b. 1892).

For weeks, I searched WWI draft registrations, federal census records, death certificates, Social Security claims, marriage records and all the birth records I could find online. But none provided new information about my main line of Carrigans. Losing hope, I came close to giving up.

But then came a breakthrough in the 1930 census (see image above): James Thomas and his wife, Lillian, lived in the household of a “cousin,” a man named Thomas Hessian. Hessian? I’d never heard the name before, but I focused my research on the newcomer. Using his name and birth year, I found him with his brother and widowed mother (Irish-born Margaret Hessian) in the 1920 census. To my surprise, I found James Thomas Carrigan and Lillian Carter listed on the same page, then unmarried and living in separate homes. The page had James Thomas, Lillian and the Hessians as neighbors. But could the relationship run deeper? Could the Hessians be Carrigans? And if so, could they provide the connection to the old country that I’ve been looking for?

Determined, I searched high and low for records that might give me Margaret Hessian’s maiden name. But her 1910 and 1920 census entries were inconsistent, giving different years for her immigration and birth. Without concrete dates, I couldn’t identify her in passenger lists, declarations of intention or vital records.

Then I located a Find A Grave entry for Thomas Hessian, who died in 1945 and was buried in St. Joseph’s New Cemetery in Cincinnati.

And that was my long-awaited pot of gold. Following a hunch, I found Thomas in the cemetery’s online index of graves. His parents’ names? Patrick Hessian and Margaret Carrigan. A match! But it gets even better: Margaret’s burial entry revealed her parents’ names as Patrick Carrigan and “X Haley.”

With this in mind, I jumped back to Irish research and revisited the “Corrigan” lead. In 1880s-era Dublin, Catholic, Irish-born James (baptized in 1854) and Mary (baptized in 1853) have as parents Patrick Corrigan and Catherine (unknown maiden name). Across the pond, Catholic, Irish-born James (born about 1856) and Margaret (born about 1854) share Patrick Carrigan and (unknown first name) Haley as parents.

So are my Carrigans the Corrigans from St. Andrew’s in Dublin? My research so far suggests that is a possibility. The discrepancies in names and vital information aren’t unusual. Mary and Margaret were similar (even interchangeable) names at the time, and birth years were less concrete in the 1800s than they are today.

But I shouldn’t start calling myself a Dubliner yet. Only more research can prove or disprove my theory. Finding the maiden name of Patrick Corrigan’s wife is a priority, as is searching Margaret’s marriage, immigration, and naturalization records for any evidence of a hometown. But with a lack of other supporting evidence, this is my best find yet, and it wouldn’t have happened if I hadn’t researched my distant Hessian cousin.

Learn more about researching your ancestors from the Emerald Isle in The Family Tree Irish Genealogy Guide.