101st Engineer Battalion ( United States ) The 101st Engineer Battalion is a branch of the Massachusetts National Guard and one of the oldest serving regiments of the United States Army . The 101st Engineer Battalion was originally established as the East Regiment . As the first muster was held on the green in Salem , Massachusetts , Salem is seen as the birthplace of the National Guard . History . On December 13 , 1636 , the Massachusetts General Court ordered the organization of three militia regiments designated as the North , South , and East regiments . The East Regiment ( later the Essex Regiment ) provided protection and support to the Settlers of the Massachusetts Bay Colony for 139 years . It also fought in the Pequot Indian Wars , the King Philips War , and the French and Indian War . The 101st played a key role in the Revolutionary War . Elements fought the Loyalists on April 19 , 1775 that started the battle for independence and an active duty regiment saved General George Washington ’ s Army after the Battle of Long Island in August of 1776 . The same element helped the American cause to remain alive in December of 1776 during the Battle of Trenton . They manned the boats for General Washington to cross the Delaware . During the Civil War , three separate Regiments were established in Essex County . The 8th Massachusetts Volunteer Militia sailed to Annapolis , Maryland in April of 1861 ; boarded the USS Constitution ; and sailed her to New York Harbor so she would not fall into the hands of the Confederates . The 19th Massachusetts Volunteer Militia fought with the Army of the Potomac and had seven Medal of Honor Recipients . The 50th Massachusetts Volunteer Militia had port duty in Louisiana and had one Medal of Honor recipient . Although the Battalion did not fight in the War with Spain , the Headquarters Company did . The Battalion was mobilized for World War I . However the Second and Eighth Massachusetts Militia were consolidated to form the 104th Infantry Regiment under the 26th Infantry Division . The remaining cadres were reorganized as the Fifth Pioneer Infantry , but was not deployed overseas . In 1920 , the 5th Pioneer Infantry ( Engineers ) was re - designated the 101st Engineer Battalion and realigned under the 26th Yankee Division , where it would remain until the Division was deactivated in 1993 . The 101st Engineer Battalion fought with the 26th Infantry Division under Patton ' s Third Army , and provided the maps to the Third Army for the relief of the 101st Airborne Division during the Battle of the Bulge . From 1993 to 2006 the 101st Engineer Battalion was aligned under the 42nd Infantry Division . In 2006 , HHC deployed to Kosovo as part of Task Force Falcon . In October 2008 , the Battalion was placed under the new 26th Maneuver Enhancement Brigade , and placed the " YD " patch back on its left shoulder . In June 2009 the Battalion mobilized for Operation Iraqi Freedom , providing Construction and Combat Engineer support to the Multi - National Division Baghdad / United States Division - Central area . For this , the Battalion earned a Meritorious Unit Commendation ribbon . Active units within the battalion . Headquarters and Headquarters Company Forward Support Company 181st Engineer Company ( Vertical ) 182nd Engineer Company ( Sapper ) 183rd Engineer Team 188th Engineer Team 189th Engineer Team ( Asphalt ) 379th Engineer Company ( Horizontal ) Campaign participation credit . Revolutionary War Civil War World War II Operation Joint Guardian Global War on Terror