The 12th Pennsylvania Regiment also known as Northampton and Northumberland Defense Battalion was an American infantry unit that fought during the American Revolutionary War as part of the Continental Army.
 The regiment was raised 23 August 1776 at Sunbury, Pennsylvania as a state militia regiment and later renamed the 12th Pennsylvania.
 In January 1777 the 12th was commanded by Colonel William Cooke at Princeton.
 Assigned to Thomas Conway's 3rd Pennsylvania Brigade, the regiment would see action at Brandywine, Germantown, and Monmouth.
 The regiment was merged into the 3rd Pennsylvania Regiment shortly after Monmouth and went out of existence.
The 9th Pennsylvania Regiment was authorized 16 September 1776 and was assigned to the main Continental Army on 27 December 1776.
 It was organized during the spring of 1777 to consist of eight companies of volunteers from Westmoreland, Lancaster, Chester, Philadelphia and Cumberland counties of the commonwealth of Pennsylvania.
 The regiment was assigned to the 3d Pennsylvania Brigade of the main Continental Army on 27 May 1777.
 On 1 July 1778 the regiment was re-organized into nine companies.
 On 22 July 1778 the regiment was re-assigned to the 2d Pennsylvania Brigade.
 It was consolidated with the 5th Pennsylvania Regiment on 17 January 1781 and re-designated as the 5th Pennsylvania Regiment and concurrently furloughed at Trenton, New Jersey.
 The regiment would see action during the Battle of Brandywine, Battle of Germantown, Battle of Monmouth and the Battle of Springfield.
The 7th Pennsylvania Regiment was an infantry unit raised on 4 January 1776 at Carlisle, Pennsylvania for service with the Continental Army during the American Revolutionary War.
 On 17 January 1777 Lieutenant Colonel Thomas Hartley transferred out of the unit to take command of Hartley's Additional Continental Regiment.
 The 7th Regiment saw action at the battles of Brandywine, Paoli, Germantown, Monmouth, Springfield and Bull's Ferry.
 At Monmouth, Colonel William Irvine led the regiment.
 The unit merged with the 4th Pennsylvania Regiment on 17 January 1781.
The 6th Pennsylvania Regiment, first known as the 5th Pennsylvania Battalion, was a unit of the United States of America (U.S.) Army, raised December 9, 1775, at Philadelphia, Pennsylvania, for service with the Continental Army.
 The regiment would see action during the New York Campaign, Battle of Brandywine, Battle of Germantown, Battle of Monmouth, and Green Spring.
 The regiment was disbanded on January 1, 1783.
The 11th Pennsylvania Regiment or Old Eleventh was authorized on 16 September 1776 for service with the Continental Army.
 On 25 October, Richard Humpton was named colonel.
 In December 1776, the regiment was assigned to George Washington's main army and was present at Assunpink Creek and fought at Princeton in January 1777.
 During the spring the unit assembled at Philadelphia, Pennsylvania in a strength of eight companies.
 The soldiers were recruited from Philadelphia and four nearby counties.
 On 22 May 1777 the regiment became part of the 2nd Pennsylvania Brigade.
 The 11th was in the thick of the action at Brandywine, Paoli, and Germantown in 1777.
 It was present at White Marsh and Monmouth.
 On 1 July 1778, the unit was consolidated with the 10th Pennsylvania Regiment and the 11th Regiment ceased to exist.
 Humpton took command of the reorganized unit.
Hartley's Additional Continental Regiment was an American infantry unit of the Continental Army that served for two years during the American Revolutionary War.
 The regiment was authorized in January 1777 and Colonel Thomas Hartley was appointed its commander.
 The unit comprised eight companies from Pennsylvania, Maryland, and Delaware.
 When permanent brigades were formed in May 1777, the regiment was transferred to the 1st Pennsylvania Brigade.
 Hartley's Regiment fought at Brandywine, Paoli, and Germantown in 1777.
 The unit helped defend the Pennsylvania frontier against Indian raids in the Summer and early Fall of 1778.
 In January 1779, following a resolution of the Continental Congress the regiment, along with Patton's Additional Continental Regiment and part of Malcolm's Additional Continental Regiment, were combined to form a complete battalion known as the "new" 11th Pennsylvania Regiment.
 The new 11th participated in the Sullivan Expedition in the summer of that year.
 In January 1781 the new 11th merged with the 3rd Pennsylvania Regiment and ceased to exist.
The 10th Pennsylvania Regiment was an American infantry unit that served in the Continental Army during the American Revolutionary War.
 Raised in September 1776 in the strength of eight companies, it was assigned to George Washington's main army in December 1776.
 Led by Colonel Joseph Penrose, the regiment fought under Thomas Mifflin at Princeton.
 In 1777 the unit was in action at Brandywine, Paoli, and Germantown during the time Adam Hubley was lieutenant colonel.
 At Monmouth in June 1778 Colonel George Nagel was in command.
 A few days after Monmouth, the regiment absorbed the 11th Pennsylvania Regiment and Colonel Richard Humpton took over the unit, which grew to nine companies in size.
 In 1780 the 10th fought at Springfield and Bull's Ferry.
 In January 1781 the 10th Pennsylvania merged with the 1st Pennsylvania Regiment and ceased to exist.
The 13th Pennsylvania Regiment, also known as The Pennsylvania State Rifle Regiment and Miles's Regiment, was raised March 6, 1776, as a state militia regiment and later for service with the Continental Army.
 The regiment would see action during the New York Campaign, Battle of Trenton, Battle of Princeton, Battle of Brandywine, Battle of Germantown and the Battle of Monmouth.
 The regiment was merged into the 2nd Pennsylvania Regiment on July 1, 1778.
The Battle of Trenton was a small but pivotal battle during the American Revolutionary War which took place on the morning of December 26, 1776, in Trenton, New Jersey.
 After General George Washington's crossing of the Delaware River north of Trenton the previous night, Washington led the main body of the Continental Army against Hessian soldiers garrisoned at Trenton.
 After a brief battle, nearly the entire Hessian force was captured, with negligible losses to the Americans.
 The battle significantly boosted the Continental Army's flagging morale, and inspired re-enlistments.
The 8th Pennsylvania Regiment or Mackay's Battalion was an American infantry unit that became part of the Continental Army during the American Revolutionary War.
 Authorized for frontier defense in July 1776, the eight-company unit was originally called Mackay's Battalion after its commander, Colonel Aeneas Mackay.
 Transferred to the main army in November 1776, the unit was renamed the 8th Pennsylvania Regiment on 1 January 1777.
 It completed an epic winter march from western Pennsylvania to New Jersey, though Mackay and his second-in-command both died soon afterward.
 In March 1777 Colonel Daniel Brodhead IV assumed command.
 The regiment was engaged at the Battles of Bound Brook, Brandywine, Paoli, and Germantown in 1777.
 A body of riflemen were detached from the regiment and fought at Saratoga.
 Assigned to the Western Department in May 1778, the 8th Pennsylvania gained a ninth company before seeing action near Fort Laurens and in the Sullivan Expedition in 1778 and 1779.
 The regiment consolidated with the 2nd Pennsylvania Regiment in January 1781 and ceased to exist.

Question: Which battle led by General George Washington did the 13th Pennsylvania Regiment participate in? 
Answer: Battle of Trenton