The Rock Creek/Union Hospital Complex is located southeast of Gettysburg along Rock Creek, White Run, and various tributaries. This area of land of 15 contiguous properties made up the hospital sites of the First, Second, Third, Fifth, Sixth, and Twelfth Corp. of the Army of the Potomac. The hospital complex occupied the high ground which rises sharply from the creeks. From July 2 to the middle of August 1863 these corps and division hospitals were in the Union rear.

The Rock Creek/White Run Union Hospital Complex encompasses the largest cluster of corp. hospitals associated with the Battle of Gettysburg. It was critical that good water be readily available, which is why this location was chosen. The district does not include all of the Union hospitals but rather encompasses some of the major treatment sites. All the hospitals were in operation until Camp Letterman was established in late Jul 1863.

The Union Hospital complex is an important part of the Battle of Gettysburg history because it cared for approximately 27,999 wounded and impacted the local citizens. The large amount of incapacitation men had to be fed, treated for wounds and their complications and sheltered from the weather. All farms in the immediate areas were pressed into service to provide for the care of the wounded for days and weeks after the three day battle.

Some of the buildings in this area postdate the battle. The landscape itself, with its terrain and other natural features, made this an attractive choice for the cluster of hospitals that survives intact to this day.

The district  has 13 properties listed on the National Register which were the hospital sites and they are listed under the historic names from the battle era. There are 11 contributing buildings where there is newer residential infill.