Short answers, pulled from the story.
The Battle of the Wilderness was fought on the 5th, 6th, and the 7th of May 1864, during the American Civil War. It was the opening battle of Ulysses S. Grant's Overland Campaign against Robert E. Lee's Army of Northern Virginia.
The Battle of the Wilderness was fought in a densely wooded area near Locust Grove, Virginia, about 20 miles west of Fredericksburg. The region, known as the Wilderness of Spotsylvania, had narrow roads and thick second growth forest that made maneuvering difficult for both armies.
Lieutenant General Ulysses S. Grant accompanied Major General George Meade's Army of the Potomac against General Robert E. Lee's Army of Northern Virginia. Grant's Union force totaled 118,700 men and 316 artillery pieces, while Lee commanded 66,140 men.
The Battle of the Wilderness produced roughly 17,666 Union casualties and 11,033 Confederate casualties, over 28,000 combined. That places it among the five costliest battles of the American Civil War.
The Battle of the Wilderness was tactically inconclusive, but Grant chose to keep advancing south toward Spotsylvania Court House rather than retreat, unlike every Union commander before him. That decision began a sustained war of attrition against Lee's army that continued until Lee's surrender at Appomattox Courthouse on the 9th of April 1865.
Confederate Lieutenant General James Longstreet was severely wounded in the neck by his own men on the 6th of May 1864, in the same stretch of woods where Stonewall Jackson had been shot by friendly fire the year before. Brigadier General Micah Jenkins was killed in the same volley.