Since September 11, 2001 the 55th Brigade has mobilized 3,032 soldiers in support of the Global War On Terror.  In 2002-03, the 55th Brigade led “Taskforce Keystone,” a major deployment of about 2,000 soldiers of the 28th Infantry Division to Central Europe to provide force protection and enhanced security in the wake of the September 11, 2001 terrorist attacks.  While Task Force Keystone was on duty, the 55th Brigade also provided the 1-109th Infantry and C Company 103rd Engineers to the 28th Infantry Division’s peacekeeping mission in Bosnia. 

The Brigade also has provided units to Operation Iraqi Freedom;
the 1-109th Field Artillery, 2-103rd Armor Battalion, C Company 103 Engineers, with the 1-109th Infantry, A Company 3-103 Armor, 228th Support Battalion currently in Iraq (February 2006). 

Appropriately, the soldiers of the 109th Infantry Regiment, the element from which the 55th was born, earned the nickname "Men of Iron" for their three-day defense against overwhelming odds during the Champagne-Marne Offensive in World War I.

In addition to fighting the Global War on Terrorism, the 55th Brigade is key asset available to the Governor and the Commonwealth to respond to various homeland security, natural  disaster, and other emergency contingencies.

• The 55th BDE is the primary Command and Control Element
  for the Joint Task Force covering the central portion of Pennsylvania.
• The 55th BDE provides support to three Regional Counter
  Terrorism Task Forces, covering 23 counties or about 1/3 of the Commonwealth.
• The 55th BDE provides a portion of the Pennsylvania’s Quick Reaction Force, capable of responding with a battalion sized element in less than 6 hours.
• In the event of a prison emergency the 55th BDE provides force augmentation, logistics and security support to six state correctional institutions, covering about 25% of the prison population.
•  In the event of a Nuclear Power Plant emergency the
  55th BDE provides force augmentation, logistics and security to 3 of Pennsylvania’s 5 power plants within the Commonwealth.
• The 55th BDE facilities and equipment support the
  statewide communications effort for SINGARS and HF radio systems.
•  The 55th BDE provides one third of the states civil disturbance resources. The Brigade's AOR covers Scranton, Wilkes-Barre and the State Capitol, Harrisburg.