The Rock Creek/Union Hospital Complex is located southeast of Gettysburg along Rock Creek, White Run and various tributaries. This area of land of 13 contiguous properties made up the hospital sites of 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 July 1863.

The Union Hospital complex is an important part of the Battle of Gettysburg history because it care for approximately 27,999wounded and impacted the local citizens. The large amount of incapacitated 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 were postdate 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 and 28 non-contributing buildings where there is newer residential infill.