See [[Massachusetts in the Civil War|Massachusetts in the Civil War]] for information about Massachusetts Civil War records, web sites, etc. with links to articles about the Massachusetts regiments involved in the Civil War. The regimental pages often include lists of the companies with links to the counties where the companies started. Men in the companies often lived in the counties where the companies were raised. Knowing a county can help when researching the families of the soldiers.
The [http://www.itd.nps.gov/cwss/ Civil War Soldiers and Sailors System] allows name searching for soldiers. The result set gives the
regiment for the soldiers. Then you can check the Wiki regiment page to determine counties. Often knowing the counties that had men in a regiment will help you determine if a soldier was your ancestor.<br>
=== '''World War I (1917–1918)''' ===