The Wounded Warrior Project offers resources and support to severely injured servicemen and women, and to their families and caregivers. The Veterans Administration exists "to care for him who shall have borne the battle, and for his widow, and for his orphan," and you can see a few more ways to do that here.
I started to call this post "Five Deadliest Battles," but people define battles in different ways, and keeping it narrow would have excluded the first operation on this list.
1. The Battle of Huertgen Forest. Germany, September 1944–February 1945; approximately 33,000 Americans dead, severely injured, or otherwise incapacitated. The longest battle in the history of the United States Army was also the longest battle on German ground during the Second World War. The Huertgen Forest is an area of about 50 square miles on the border of Germany and Belgium; the badly-outnumbered German army (80,000 troops vs. 120,000 Americans) was determined to hang onto the land as a staging area for its planned Ardennes Offense (which became the Battle of the Bulge). The Germans lost 28,000 troops, of whom 12,000 were killed, but managed to hang onto the territory long enough to launch their last major Western Front attack from there.
2. The Meuse-Argonne Offensive (Battle of the Argonne Forest). France, September–November 1918; approximately 117,000 American casualties, with 26,277 U.S. soldiers killed. The biggest, deadliest battle of the First World War was launched by the American First Army, under General Jack Pershing, and the French Fourth Army, under General Henri Gourand, against the Germans under Georg van der Marwitz. It was the first battle of the Grand Offensive that eventually broke the Germans' Western Front, including the Fifth Battle of Ypres, the Battle of St. Quentin Canal, and the Battle of the Canal du Nord. Although this was the war's deadliest battle, approximately twice as many American soldiers (53,000) died of influenza between 1918 and 1919.
3. The Battle of the Bulge (Ardennes Offensive). Belgium, Luxembourg, and Germany, December 1944–January 1945; approximately 89,500 American casualties, of whom 19,000 were killed. After the grinding misery of the Battle of Huertgen Forest, the Germans concentrated their forces for a decisive attack on the Allied lines along the Western Front. The plan was to break the British-American line in the Ardennes Forest and march on Antwerp, Belgium, then to spread out again and surround the Allied armies, forcing a surrender. Thank God, it didn't work. Because of the number of troops involved (more than 840,000 men in four Allied armies, as many as 500,000 German soldiers), the Battle of the Bulge was the bloodiest of the Second World War, killing 3,000 civilians as well as the 19,000 American soldiers, at least 200 British soldiers, and German casualties of between 67,000 and 120,000. On January 7, 1945, Hitler agreed to withdraw German troops from the Ardennes. Winston Churchill called it "the greatest American battle of the war," to be "regarded as an ever-famous American victory."
4. The Battle of Okinawa. Ryukyu Islands, Japan, April–June 1945; 12,513 American soldiers killed, 38,916 wounded, 33,096 non-combat losses. The bloodiest battle of the Pacific War raged even as the Allied armies celebrated victory in Europe (V-E Day: May 8, 1945). The island of Okinawa, 340 miles from "mainland" Japan, was to be the Allies' base for air operations during the planned invasion of Japan. The Battle of Okinawa began with the largest amphibious assault in the Pacific theater: 183,000 Army soldiers and Marines, supported first by the British Pacific Fleet, then by the U.S. Fifth Fleet, and finally by the U.S. Third Fleet. The Battle of Okinawa was fought on air, land and sea. As many as 150,000 civilians on the island died, some as a result of suicide orders (with hand grenades) distributed by the Japanese military. Ninety percent of the buildings on the island were destroyed. Having conquered the island, the Allies established a military base there, and Kadena Air Base on Okinawa is still the U.S. Air Force's hub in the Pacific.
5. The Battle of Gettysburg. Pennsylvania, July 1–3, 1863; 3,155 deaths on the Union side, 4,708 on the Confederate side. After the Battle of Fredericksburg in 1862, Confederate Army General Robert E. Lee famously said, "It is well that war is so terrible. Otherwise we would grow too fond of it." He was coming off a win at the battle of Chancellorsville when he led the Army of Northern Virginia up through the Shenandoah Valley to Pennsylvania, possibly with the idea of eventually taking Philadelphia. Union troops led by Major General Joseph Hooker pursued them, but it was General George Meade who engaged Lee's army at Gettysburg. More than 50,000 troops were injured or killed by the end of the three-day battle. Lincoln delivered his Gettysburg Address in November of that year, at the dedication of a cemetery that held both Union and Confederate dead. (Most of the Confederate dead were removed, years later, and reburied at Hollywood Cemetery in Richmond, VA.)
It is for us the living, rather, to be dedicated here to the unfinished work which they who fought here have thus far so nobly advanced. It is rather for us to be here dedicated to the great task remaining before us — that from these honored dead we take increased devotion to that cause for which they gave the last full measure of devotion — that we here highly resolve that these dead shall not have died in vain — that this nation, under God, shall have a new birth of freedom — and that government of the people, by the people, for the people, shall not perish from the earth.