• January 14 - John Digges obtains 10,000 acres from Charles Calvert, fourth Lord Baltimore. Part of this land, called "Digges' Choice," will become Hanover.

• Catholics start the Conewago Settlement in the vicinity of Hanover.

• Richard McAllister settles in the area.

• Michael Tanner [Danner] suggest the name "Hanover" for the new town.

• Richard McAllister entertains Benjamin Franklin, who is on his way to Frederick, MD.

• Mary Ann Furnace was built.

• Richard McAllister officially founds Hanover, Pennsylvania.

• Caspar Reinecker builds his first tavern at 34 Frederick Street.

• George Nace begins the first Hanover tannery.

• Emmanuel Reformed Church constructs its first church.

• Caspar Reinecker opens a larger establishment across the street from his first tavern.

• John Heiser, the first brick maker on record in Hanover, sells his inn to Richard McAllister for 330 pounds.

• Thomas Jefferson passes through town, staying at Caspar Reinecker's tavern.

• Martha Washington spends a night in Hanover on her way back from Valley Forge.

• Thomas Jefferson passes through town for the second time, this time with his daughter and a servant, staying the night at the same tavern as his first visit. By this time, the tavern is known as The Sign of the Horse and is run by Alexander Forsythe.

• Jacob Shorb begins the first wire mill.

• Conewago Chapel is erected.

• July 2 - George Washington eats breakfast at The Sign of the Horse, the tavern run by Alexander Forsythe.

• Richard McAllister, founder of the town, dies.

• April - W.D. Lepper and E. Stettinius establish the Pennsylvania Wochinscrift, Hanover's first newspaper.

• Clockmaker/later congressional representative Jacob Hostetter establishes a brass foundry to cast parts for tall case clock works.

• April 4 - Daniel P. Lange and J.P. Stark issue the Hanover Gazette, another German language newspaper.

• Hanover holds its first Methodist Episcopal service.

• August 28 - Two infantry companies leave Hanover for Baltimore and will take part in the Battle of North Point fifteen days later.

• Farmer’s Market House replaces the Maypole in Center Square.

• Hanover Borough is incorporated.

• Hanover's first volunteer fire fighting organization is formed.

• August - Rev. Jacob H. Wiestling issues the Guardian, Hanover's first English language paper.

• St. Matthew's Lutheran Church organizes the first Sunday school in the community.

• Joseph Schmuck and Dr. Peter Mueller begin publishing the Intelligenceblatt.

• Philip Wolf establishes a glove factory. It will later become the Hanover Glove Company.

• Seth Forrest establishes a school on Frederick Street.

• Samuel Martin and Frederick Borgen each open a school.

• George Frysinger starts the Herald, an English language paper.

• The Hanover Saving Fund Society is established.

• Free public schooling begins in Hanover.

• George Van de Linde founds a school.

• Peter S. Alwine begins burning brick on his farm.

• James Buchanan delivers a speech in Hanover, supporting Franklin Pierce for president.

• Train service to York and Baltimore departs from depot in the Hanover Commons.

• Hanover Borough Council passes an ordinance that the Hanover Square will now be called the Diamond. The ordinance is basically ignored.

• Railroad lines are extended to Gettysburg.

• General John E. Wool brings a division of troops to Hanover, but they leave after two days and head back to Baltimore.

• June 30 - The Battle of Hanover takes place when General J.E.B. Stuart’s Confederate cavalry attacks a Federal cavalry regiment.

• November 18 - Lincoln stops in Hanover on his way to Gettysburg for the dedication of the Soldiers National Cemetery.

• St. Mark's Lutheran Church is organized, becoming the first English-speaking Lutheran church in Hanover.

• Famous Pennsylvania war governor, Andrew Curtin, delivers a speech in Hanover in efforts to reelect Lincoln.

• The Gazette newspaper discontinues its publication.

• U.S. Grant, on his way to Gettysburg to campaign for the presidency, stops briefly in Hanover due to his train's engine trouble.

• The first YMCA of Hanover is organized.

• Cyrus Diller uses a team of horses to pull the Farmer's Market House flat. An elaborate fountain is put in its place.

• St. Joseph's Catholic Church is erected.

• November 29 – Etzler and Young's grain warehouse collapses.

• The borough purchases the Hanover Steam Fire Engine for $4,400.

• The Hanover Creamery opens.

• The Mennonite church is built.

• February 22 – The fire company tests its Silsby Steam Engine.

• The borough limits are extended by 303 acres.

• Hanover Branch Engine No. 3, the train that carried Lincoln to Gettysburg in 1863, is cut up for scrap.

• St. Paul's Lutheran is organized.

• The Hanover Street School is erected.

• The borough limits are extended by 93 more acres.

• Regular high school graduations begin.

• A crippling snowstorm hits Hanover.

• Downtown Hanover’s Heisler Shoe Company becomes Sheppard & Myers Shoe Company (also known as Hanover Shoe).

• The Church of the Brethren is formed.

• August 12 – A fire engulfs several blocks in downtown Hanover.

• Eichelberger High School is erected.

• The United Evangelical Church is built.

• Hanover Printing Company is incorporated.

• "The Picket" statue is unveiled in the center of the Square.

• St. Vincent's Memorial Church is established.

• Grace Reformed congregation is organized.

• Harry V. Warehime founds Snyder's of Hanover.

• The present YMCA organization is effected.

• The Hanover Public Library opens.

• The U.S. Post Office in Hanover is completed.

• The American Machine and Foundry catches fire for the second time and is nearly leveled.

• Hanover celebrates its centennial.

• A tornado rips through downtown Hanover.

• February 8 – The Sun Publishing Company begins the Evening Sun.

• Lancers Drum and Bugle Corps, a 100+ member marching band, is founded.

• UTZ Quality Foods, Inc. is established.

• Nicholas E. Mavros opens Hanover's first fast food restaurant. It will later become known as the Famous Hot Weiner.

• A tree used by General Custer to tie his horse and later used in ceremonies for Civil War veterans is removed and a marker is placed in its spot.

• Hanover Foods Corporation is begun.

• Hanover General Hospital opens.

• Elsner Engineering Works founded by Franz and Johanna Elsner, German immigrants.

• September 2 – Hanover throws a Welcome Home party for soldiers returning home from World War II.

• The Lincoln Marker on Railroad Street is dedicated.

• Capital Bakery opens a plant in Hanover.

• The last of the Hanover cigar manufacturers closes.

• The Hanover Area Historical Society is begun.

• December – The Codorus Creek is dammed and the community of Marburg is flooded to create Lake Marburg (Codorus State Park).

• "The Picket" statue is moved to the north corner of the Square.

• South Western High School opens.

• Link's Music is established in downtown Hanover.

• The Hanover Symphony Orchestra is established.

• B.C. Schuchart, Inc. is sold to Shipley Oil.