• Our Ancestral St Clairs of Herdmanston

    Click Here
  • Learn More About Our Exeter New Hampshire Lineage

    Click Here
  • Introducing Our Aberdeen Lineage

    Click Here
  • Our Ancestral Caithness and Orkney Lineage

    Click Here
  • Research: Who’s Who in the Roman de Rou

    Click Here

This is the official website of the St Clair Sinclair DNA Study. We help those with our surnames – and our affinity families – get the information to prove when they connect to one of our 14+ lineages. Take a look around at one of the most robust family DNA studies on the Internet and get in touch if you want to use genetics to solve your Saint-Clair genealogy.








Big Y Tested

From Our Blog

Subjects We’ll Be Covering in the Blog

  • Medieval benefaction
  • Saint-Clair geography
  • Affinity families
  • DNA science news
  • Member updates
  • Relevant archaeology news
  • Tips & tricks
  • DNA results interpreted
  • Strange Saint-Clair facts
  • Book reviews
  • Lineage genealogy news
  • Guest bloggers
  • New historical research
  • Sorting fact from fiction
  • Etc.

Tracking the Geography of Early Sinclair / St Clair  History

Click here to launch an interactive map. Scroll up the map and roll your mouse over the numbers to track the Saint-Clair name from Normandy, to England, and up into Scotland, Ireland, and the isles.

An appeal for getting all our lineages Big Y 700 tested

In the last few years, Family Tree DNA’s Big Y test has helped us achieve a level of understanding about our family we never thought possible when we began the study in 2004.

The newer Big Y 700 test is the latest advancement from Family Tree DNA. In order to identify SNPs for each lineage within the early medieval to genealogical timeframe – our target age range – we need a minimum of two members in each lineage to take the Big Y 700 test. We’re asking for help from each lineage member to chip in to the “general fund” with FTDNA. You can direct which lineage your donation benefits.

It could be $10-20 donation, or preferably more if you can. So please consider donating if you wish to explore further possibilities for your specific lineage.

Click the “donate” button below.  You can specify which lineage fund you wish the donation to go toward. If you are unsure which one, please visit the results page (here).

Featured Video of the Month

Managing Settings

In this video we show you the best way to manage your personal kit settings so you and others can maximize the usefulness of DNA testing.

See this video, and our entire set of training videos at our Resources section, where we guide you through the steps of DNA testing and understanding your results every step of the way.

Ready to Get Started with DNA Testing?

Ready to find out which of our many DNA lineages you connect with? Please include a note about your suspected connection to the Sinclair / St Clair family so we can recommend the right test for you. We’ll send you back a link to order the kit.

What Others are Saying About St Clair Research

I found you during my research and really enjoyed your web site which is very well done – congratulations.


First, I’d like to thank you and the St Clair family DNA testing group for the amazing work you have all done. Your website and blog have been like black holes that I’ve enjoyed falling into. Thank you once again for the incredible work.


I have just recently found your St. Clair research videos and your website. What terrific research! And written so well. Thank you for rekindling my interest in all this. This is great!


Thank you for taking such an interest in helping my father solve his genealogy before he passed away. It was a great comfort to him.