I. Start with what you know

Begin at home, not in Ireland. Every serious genealogist will tell you the same thing: write down every name, date and place you already know before you touch a database. Interview older relatives while you can. Photograph the backs of old photographs. Collect christening cards, death notices, prayer cards, school certificates — they will carry you further than any subscription site.

Once you hit a generation that emigrated from Ireland, or a generation who stayed, the trail forks. From that point each of the resources below has a different strength.

II. The Clan's own archive

The Clan maintains research databases built up over decades by Clan researchers, covering the O'Dowd name and its main variants:

• All Irish births for O'Dowd and variants, from the beginning of parish records through 1900, indexed by county and parish.
• Irish marriages and deaths to 1860 (work is underway to extend these to 1900 before the next Clan gathering).
• UK births, deaths and marriages for O'Dowd and variants, 1837–1900.
• Irish census material, 1821–1911.
• Passenger ship records, currently being expanded.

These collections are available to registered Clan members. If you hit a wall on one of the public sites, they are often the fastest way through it for an O'Dubhda family.

III. The free Irish records you should try first

Ireland is, in one sense, very lucky: the core civil and ecclesiastical records are now free online. Before paying for anything, work through these.

Irishgenealogy.ie

The official Irish government site. Free. Civil registration of births (from 1864), marriages (from 1845) and deaths (from 1871), with indexes and — for older records — images of the original register pages. Also includes Roman Catholic and Church of Ireland parish registers for several counties. Start here for anyone born in Ireland after 1864.

The National Archives of Ireland census site

At census.nationalarchives.ie. Free. The 1901 and 1911 Census of Ireland in full, searchable by every individual in the household, along with fragments surviving from earlier (1821–51) censuses. The 1901 and 1911 returns are the single most useful record set for most Irish families because the destruction of the Public Record Office in 1922 took so much else with it.

Griffith's Valuation (1847–64)

At askaboutireland.ie. Free. A household-by-household property valuation covering all of Ireland in the generation after the Famine. For many O'Dubhda families this is the closest thing to a replacement census for the 1850s and places your ancestor in a specific townland.

The Tithe Applotment Books (1823–37)

Also free, via the National Archives. The earlier parallel to Griffith's, recording occupiers of tithable land. Essential for tracing families back into the first half of the nineteenth century.

RootsIreland.ie

Run by the Irish Family History Foundation — the network of county-based heritage centres, including Sligo and Mayo. Paid subscription, but the only comprehensive index of Catholic parish baptisms and marriages for many counties, transcribed in-country. For Tireragh and Tirawley families this is often decisive.

IV. The commercial platforms

The big subscription sites add value in three ways: they aggregate records that are otherwise scattered, they link records to family trees, and they match your DNA results. For Irish work in particular:

Ancestry (ancestry.com / ancestry.co.uk)

The largest platform and the one most American O'Dowds will meet first. Strongest for US federal and state records, immigration and naturalisation, newspapers, and UK civil registration. Its Irish parish register collection is good but overlaps with FamilySearch. Its DNA service — AncestryDNA — has by far the biggest pool of testers, which makes it the best starting point for cousin matching.

FindMyPast

Owned by a British–Irish partnership and often the strongest single site for Irish research. Holds the Catholic Parish Registers, the Landed Estates court rentals, Irish newspapers (in partnership with the Irish Newspaper Archive) and a very large body of Irish petty sessions, workhouse and Poor Law records. If you are tracing a nineteenth-century Irish family, FindMyPast usually repays the subscription fastest.

MyHeritage

Strongest in continental Europe and increasingly aggressive on DNA. Its Record Matches and Smart Matches features are genuinely useful if you already have a tree uploaded. For O'Dowd families that scattered into the Americas, Australia and mainland Europe, MyHeritage often surfaces connections the other sites miss.

FamilySearch.org

Run by the Church of Jesus Christ of Latter-day Saints. Free. The largest free genealogy database in the world. Holds microfilmed images of Irish Catholic and Church of Ireland parish registers, US and UK vital records, and an ever-growing body of indexed Irish material. Even if you subscribe to Ancestry or FindMyPast, always check FamilySearch as well — it is sometimes the only source for a particular register.

V. DNA testing for Irish ancestry

DNA testing will not, on its own, tell you which O'Dubhda you descend from. What it will do is connect you with living cousins whose trees — combined with yours — can break through brick walls. Four services matter:

• AncestryDNA — the biggest database, the best for finding cousin matches. If you only test one place, test here.
• MyHeritage DNA — strong European coverage and a useful "Theory of Family Relativity" feature that stitches your matches to documentary trees.
• 23andMe — strong on health reporting and deep ancestry, weaker on genealogical cousin matching. Worth transferring the raw file elsewhere once you've tested.
• FamilyTreeDNA — the only major service still offering Y-DNA and mitochondrial testing. Y-DNA follows the male line — the same line the O'Dubhda surname follows — and is what you need if you want to join a surname DNA project for O'Dowd/O'Dubhda.

VI. Heritage centres and help through the Clan

For many families the single most efficient step is simply to contact one of the county heritage centres in the old O'Dubhda homeland. They hold the indexed parish registers locally and will do a search for a fee that is usually modest compared to what a commercial tree-builder charges.

County Sligo Heritage and Genealogy Society

Stephen Street, Sligo. Website: sligoroots.com (also reachable via irishroots.net/sligo). Email: heritagesligo@eircom.net. Indispensable for Tireragh — the core O'Dubhda territory.

Mayo North Family History Research Centre

Enniscoe, Castlehill, Ballina. Website: mayo.irish-roots.net. Email: normayo@iol.ie. Covers the Mayo side of the old O'Dubhda country, including the Erris and Tirawley branches.

Connect through the Clan

The Clan itself can put paid-up members in touch with experienced genealogical researchers who know the O'Dowd name and its main variants. This is a volunteer channel, not a commercial service, and availability depends on who is active at any given time — but for an O'Dubhda line it is often the shortest route to someone who already knows the ground.

Our Clan rallies are also a good place to get hands-on help. Bring what you have — names, dates, townlands, a family tradition — and longstanding Clan researchers are usually on hand to point you toward the right record set or help you read an old parish register. To arrange either, join the Clan first if you have not already, then get in touch.

If you are writing to the heritage centres, include as much as you can: the full name of the person you are researching, approximate dates, and the townland, parish, barony or county where they lived. The more specific the brief, the faster they can work.

VII. A last word

No single site will give you your full O'Dubhda line. A typical successful search moves between several — starting from the living memory of your own family, working back through irishgenealogy.ie and the 1901/1911 census, confirming with parish registers on FindMyPast or RootsIreland, widening out with Ancestry and MyHeritage DNA matches, and finally — in the difficult cases — asking a heritage centre or a researcher who knows the ground.

The Clan is here to help at each step. When you find something, tell us: every new record added to the collective archive makes the next cousin's search a little shorter.