Many wars or conflicts in U.S. history have federally designated “periods of war,” dates marking their beginning and ending. These dates are important for qualification for certain veterans’ pension or disability benefits. Confusion can occur because beginning and ending dates for “periods of war” in many nonofficial sources are often different from those given in treaties and other official sources of information, and armistice dates can be confused with termination dates. This report lists the beginning and ending dates for “periods of war” found in Title 38 of the Code of Federal Regulations, dealing with the Department of Veterans Affairs (VA). It also lists and differentiates other beginning dates given in declarations of war, as well as termination of hostilities dates and armistice and ending dates given in proclamations, laws, or treaties. The dates for the conflicts in Iraq and Afghanistan are included along with the official end date for Operation New Dawn on December 15, 2011. This report will be updated when events warrant.