American military commemorative medals, established by Congress to reward a particular individual for some noteworthy event or personal achievement, have a long and distinguished history. The first was awarded to General George Washington for his recovery of Boston on March 17, 1776. The earliest American military commemorative medals were struck in Paris, but since the War of 1812 most of them have been prepared by the United States Mint. Numerous military and naval battles and their commanders have been commemorated by medals authorized by Congress, and prior to the use of campaign medals these were virtually the only Federal medals awarded for noteworthy military events. Note, however, that these medals were not awarded to everyone who participated in the event being commemorated: they were only given to specific individuals (usually the senior commander). After the use of campaign and service medals became common, the creation of military commemorative medals by Congress for award to specific individuals diminished, even though they continue to be authorized from time to time. Among the most recent were those authorized by Congress for Generals Colin Powell and Norman Schwartzkopf following the Gulf War against Iraq. 

The commemorative medals now awarded by Congress to specific individuals are designated as "national medals" and are awarded in gold. However, from time-to-time Congress also creates military commemorative medals that recognize all individuals who participate some special event or circumstance. These medals are very similar to conventional campaign medals; in fact, they differ from them primarily because they are created by Congress rather than by the President (through an Executive Order) or by the military itself. An interesting exception to the "normal" way of establishing campaign and service medals occurred when Congress established campaign medals for Afghanistan and Iraq. Congress did so only because the Department of Defense refused to, in spite of great pressure from veterans groups and others. The same thing happened in the case of the Korea Defense Service Medal the Department of Defense refused to establish that particular medal, so Congress created it through legislation. Thus, although the Afghanistan and Iraq Campaign Medals are classic campaign medals, they are technically "commemorative" medals because they were created by Congress. Likewise, the Korea Defense Service Medal is a classic "service medal," but is also technically a commemorative medal because it was also created by Congress. 

The military commemorative medals described in this section do not include those authorized by Congress prior to the Spanish-American War, as they are adequately described elsewhere. The decision to classify a medal as a "military commemorative medal" in this listing is based on a two criteria: the medal must have been specifically authorized by Congress, and it must commemorate some specific military event or action. 

The first commemorative medal established following the Civil War was the Dewey Medal, which commemorated the stunning naval victory at Manila Bay on May 1, 1898 (Congress authorized this medal a little over a month after the battle). Perhaps more commemorative medals were established for the Spanish-American War than for any other event. Likewise, a series of five medals was established by Congress over a thirty year period (1930-1960) to commemorate polar explorations - including one that was established 36 years after the event it commemorated. These medals include the Peary Polar Expedition Medal (1908); the Byrd Antarctic Expedition Medal (1928-1930); the Second Byrd Antarctic Expedition Medal (1933-1935); the United States Antarctic Expedition Medal (1939-1941); and the Antarctica Service Medal. 

Some commemorative medals are wearable and have a suspension ribbon just like any other medal. Others, the so-called "table medals," are larger in size and do not have a ribbon. In three cases (the Cardenas Medal of Honor, Walter Reed Medal, and the NC-4 Medal), Congress authorized smaller "wearable" medals to be issued to their recipients. These so-called "miniatures" are the same size and configuration as ordinary full-sized medals, and are extremely rare.