World War I, which began a century ago this summer, is the focal point of many records helpful to genealogists.

The United States did not enter the war until 1917 and held three draft registrations in 1917 and 1918 for all eligible men between the ages of 18 and 45 (with ages for each registration differing). That included one of my grandfathers and two of my great-grandfathers.

The value of the registration cards is that they cover all the men who registered, not just those who served, and document their full name, date of birth, often the place of birth, occupation, address and who they were living with at the time of registration. Plus, their actual signatures — for one of my ancestors that is the only example we have.

These World War I draft registration cards are scanned and indexed on Ancestry.com, the originals being at the National Archives at Atlanta in Morrow. They cover the entire country.

There are also World War I service cards available for some states, so check for those (Georgia for sure) on Ancestry or via a particular state’s archives. These would be just for the men who served.

County courthouse records often contain a military discharge book, covering discharge papers from several wars. Georgia also published a book, “Georgia’s Participation in the World War…” (1936), about those who died in the war. The Georgia dead are also listed on a large plaque in front of the Floyd Office Towers across from the state Capitol.

For anyone who died and is buried overseas, check abmc.gov.

Many county courthouses have plaques or monuments listing who served in the war and who died, as do many county histories.

Always note in your family history who served in any wars.

Scots-Irish research

“Scots-Irish Genealogy Research” by Brian Mitchell, noted Irish genealogist, is the latest four-page laminated quick sheet in the Genealogy at a Glance series.

Mitchell covers the definition of “Scots-Irish,” the background, various places of origin and passenger list situations, and how you can use family names — to some extent — to figure out the origins.

He cites church registers, census substitutes and estate records as sources, includes two short case studies, and lists record repositories and their websites.

The cost is $8.95 plus $5.50 postage from Genealogical Publishing Co., 3600 Clipper Mill Road, Suite 260, Baltimore, MD 21211. For more information: 1-800-296-6687, genealogical.com.