| 1609 | Henry Hudson sounds the waters of the lower Delaware River and Bay. 1615-16 Etienne Brule explores Susquehanna River from headwaters to mouth. |
| 1616 | Captain Cornelius Hendrickson ascends Delaware River to mouth of Schuylkill River. |
| 1634 | Virginia voyagers sail up Delaware and establish small fort at mouth of Schuylkill. |
| 1638 | Post (Fort Christina) at what is now Wilmington, Delaware, established. |
| 1641 | 60 English Puritans from Connecticut make unsuccessful attempt to settle at mouth of Schuylkill. |
| 1643 | Swedish expedition under Johan Printz makes first permanent settlement within present borders of Pennsylvania, at Tinicum, and sets up first local government and courts; builds first mill on Cobbs Creek. |
| 1645 | Dutch in Manhattan send expedition to Schuylkill to erect Fort Beversrede. |
| 1651 | Peter Stuyvesant, Dutch governor at Manhattan, builds Fort Casimir at Sand HookNew Castle, Delaware). |
| 1654 | John Classon Rysing, new Swedish governor, captures Fort Casimir from Dutch. |
| 1655 | Stuyvesant sends expedition to the Delaware and conquers the Swedes. |
| 1664 | Colonel Richard Nicolls establishes rule of Duke of York in Delaware region. |
| 1673 | English lose control of Delaware region for a brief period. |
| 1674 | English claims secured by Treaty of Westminster. |
| 1681 | Charles II grants William Penn almost all of what is now Pennsylvania. |
| William Markham, Penn's cousin and deputy governor, arrives about July 1. |
| Three commissioners select site of Philadelphia. |
| 1682 | Duke of York relinquishes Pennsylvania and 'lower counties (Delaware) to William Penn. |
| Penn sends Thomas Holme, surveyor, to America in June to lay out town of Philadelphia |
| Penn arrives at New Castle, Delaware, Oct. 27, and at Upland (Chester) |
| Oct. 29, reaching Philadelphia a few days later. |
| Penn's 'Frame of Government' drafted in April. |
| Counties of Philadelphia, Bucks, and Chester created prior to Nov. 8. |
| First session of the assembly held Dec. 4-7, when 'Act of Union' and 'Act of Naturalization' are passed. |
| Penn issues writs for an election. |
| 1683 | First council and assembly meet at Philadelphia March 10 and accept Frame of Government on March 19. |
| New 'Charter of Liberties' enacted April 2. |
| First trial for witchcraft held in February. |
| First grand jury summoned May 2. |
| Germantown founded by Francis Daniel Pastorius. |
| First glass factory established at Frankford (now part of Philadelphia). |
| Maryland commissioners order Chester residents to evacuate, and warn settlers at Marcus Hook not to pay quitrent to Penn. |
| 1684 | Penn sails for England Aug. 17. |
| 1686 | Penn takes executive power away from council. |
| 1687 | Brewing of malt liquors on a commercial scale begun by Anthony Morris of Philadelphia. |
| 1688 | Quakers begin fight against Negro slavery. |
| 1689 | Penn arrested in England several times as a treason suspect. |
| 1690 | America's first paper mill erected by William Rittenhouse in Wissahickon Valley, Philadelphia. |
| 1692 | William and Mary deprive Penn of governing authority over Pennsylvania Oct. 20. |
| 1694 | Full proprietary rights restored to Penn Aug. 20. |
| 1699 | Penn leaves England for Philadelphia and arrives at Chester with his wife, daughter, and secretary, Nov. 28. |
| 1701 | Charter of Privileges confirmed by assembly on Oct. 28. Philadelphia chartered as a city. Penn sails for England Nov. 3. |
| 1703 | Delaware forms its own assembly and withdraws from the Province, but retains the same governor as Pennsylvania. |
| 1708 | Penn mortgages his province for £6,600. |
| 1710 | Influx of Germans, Scotch-Irish, and French Huguenots begins; between 3,000 and 4,000 Germans settle in province. |
| 1716 | Thomas Rutter builds first iron forge in province near Pottstown. |
| 1718 | Penn dies in England July 30. His second wife assumes control of province. |
| 1723 | Benjamin Franklin arrives in Philadelphia from Boston. First paper money issued in Philadelphia. |
| 1724 | Carpenters' Company organized in Philadelphia. |
| 1727 | Hannah, second wife of William Penn, dies. Germans, Swiss, and French Huguenots settle south of Lehigh Mountains. |
| 1729 | Lancaster County formed. |
| 1730 | Systematic operation of copper mine in Lancaster County begins. |
| 1732 | First steel manufactured by Samuel Nutt at his Coventry Forge, in Chester County. |
| 1736 | About 40,000 German settlers now in province. |
| 1737 | Infamous 'Walking Purchase' transacted Sept. 19, 20. |
| 1744 | Benjamin Franklin perfects discoveries of Desaguliers and Ganger in stove that bears his name. |
| 1746 | John, son of William Penn, dies. |
| 1746 | First nail factory and first rolling and slitting mills built by John Taylor at Glen Mills on Chester Creek. |
| 1749 | York County formed. |
| 1752 | Berks County formed. |
| 1753 | French begin erecting chain of forts in gateway leading to Ohio Valley. |
| Conference held with Indian tribes at Carlisle and treaty signed in October. |
| George Washington sent to interview French commander at Fort Le Boeuf. |
| 1754 | Captain Trent, with a Virginia company, begins building fort at the forks of the Ohio; |
| French capture uncompleted fort and name it Fort Duquesne. |
| Washington attacks French party at Great Meadows, kills 10, the remainder surrendering. |
| Washington is attacked by French July 3 and surrenders Fort Necessity. |
| Albany treaty with Iroquois Confederacy signed. |
| 1755 | General Braddock defeated on the Monongahela July 9; |
| Indians ravage frontiers. |
| 1756 | Governor Morris declares war against Delawares. |
| 1758 | Grand council held with Delawares and Iroquois at Easton Oct. 23, the Indians agreeing to a peace. |
| French destroy Fort Duquesne and withdraw. |
| 1759 | Fort Pitt completed. |
| War with French in Pennsylvania terminated. |
| Bituminous coal discovered near Pittsburgh. |
| 1762 | Anthracite discovered in Wyoming Valley. |
| 1763 | Pontiac's War with English breaks out; |
| Forts Presque Isle, Le Boeuf, and Venango fall before Indian assaults. |
| Indians defeated in Battle of Bushy Run. |
| 'Paxton Boys' murder peaceful Indians at Lancaster Dec. 27. |
| Settlers in Wyoming Valley driven out by Indians. |
| William Henry of Lancaster builds first steamboat in America. |
| 1764 | Colonel Henry Bouquet forces Indians at Muskingum, Ohio, to sue for peace. |
| Anti-Proprietary party urges King to purchase province. |
| 1765 | Stamp Act, passed in March, bitterly opposed by Pennsylvanians. |
| 'Baron' William Stiegel starts operation of glass works near Manheim, Lancaster County. |
| 1766 | Stamp Act repealed. |
| 1767 | Townshend Acts anger colonists. Mason and Dixon survey of Pennsylvania-Maryland boundary concluded. |
| 1768 | Pennsylvania assembly demands 'no taxation without representation. |
| Fort Stanwix Treaty with Indians, Nov. 5, settles grievances. |
| 1769 | 'Pennamite-Yankee War' begins as Connecticut pushes settlement of Wyoming Valley. 1773 Resolution adopted by Philadelphia declares whoever receives or sells tea is an enemy of his country. 1774 Committees of correspondence organized; provincial meeting of deputies held July Is. |
| 1774 | First Continental Congress meets in Carpenters' Hall, Philadelphia, Sept. 5. |
| Continental Congress adopts a 'non-importation, non-consumption, and non-exportation' agreement Oct. 20. |
| 1775 | Pennsylvania expedition fails to effect entrance into Wyoming Valley, where Connecticut has 17 settlements. |
| Pennsylvania Abolition Society founded. |
| Provincial delegates from counties meet in January. |
| Pennsylvania assembly rejects compromise plan of House of Commons. |
| Second Continental Congress meets at State House, Philadelphia, May 10. |
| Congress for first time speaks of 'the twelve united colonies' June 7. |
| Washington elected commander-in-chief of Continental Army. |
| Committee of safety organized in July. |
| 1776 | Provincial conference of deputies meets in Philadelphia June 24 to consider Declaration of Independence. |
| Provincial convention instructs Pennsylvania delegates in Congress to vote for independence. |
| Independence resolution passed by Congress July 2. |
| Declaration accepted July 4. |
| Provincial convention prepares new constitution. |
| New government begins Nov. 28 with convening of general assembly. |
| Supreme council begins to function March 5. |
| Pennsylvania 'navy' forces retirement of two British ships of war to their base May 8. |
| Pennsylvania troops engage in Battle of Long Island in August. |
| Proprietaries, John and Thomas Penn, ousted. |
| Continental Congress adjourns to meet again Dec. 20 in Baltimore. |
| Washington crosses Delaware and defeats British at Trenton Dec. 26. |
| 1777 | Congress demands oath of allegiance to Commonwealth. |
| Congress adopts flag design June 14. |
| British fleet enters Delaware Bay, but achieves no success. |
| Washington defeated at Brandywine Sept. 11. |
| Congress adjourns Sept. 18 to meet in Lancaster for one day, Sept. 27. |
| American force defeated at Paoli Sept. 20. |
| Howe enters Philadelphia Sept. 26. |
| Congress removes to New York Sept. 30. |
| Battle of Germantown Oct. 4 results in American defeat. |
| Washington goes into winter quarters at Valley Forge Dec. 19. |
| 1778 | Congress provides for confiscation of property and lands of Tories. |
| British evacuate Philadelphia June 18. |
| Congress again convenes at Philadelphia July 2. |
| Wyoming Massacre perpetrated by Indians and Tories July 2-4. |
| Pennsylvania ratifies Articles of Confederation July 9; Congress finally adopts them Nov. 15. |
| 1779 | Assembly settles proprietary claims for £130,000. |
| 1780 | Pennsylvania passes first abolition law. |
| 1782 | Congress by the Decree of Trenton decides in favor of Pennsylvania in the Wyoming Valley boundary dispute. |
| 1783 | 3,000 Pennsylvania troops march on Philadelphia to obtain from Congress 'prompt settlement of their accounts.' Sugar refining begun at Philadelphia. |
| 1784 | By treaty the whites acquire all lands in the province not previously surrendered by the Indians, Oct. 23. Second Pennamite War begins. |
| 1785 | Philadelphia Society for Promoting Agriculture founded. |
| 1787 | Constitutional convention meets in Philadelphia on May 14; Constitution of the United States signed on Sept. 17; Pennsylvania ratifies it on Dec. 12. |
| 1789 | New York agrees to accept the 42° of latitude as a boundary. |
| 1790 | New constitution for Pennsylvania adopted September 2. |
| Thomas Miffin becomes first governor. |
| United States Congress removes from New York to Philadelphia, opening sessions Dec. 6. |
| First Federal census gives Pennsylvania a population of 434,373. |
| 1791 | Bank of the United States established Feb. 25. |
| Philadelphia carpenters strike for 12-hour day. |
| 1792 | United States Mint established in Philadelphia April 2. |
| Pennsylvania buys Erie Triangle. |
| Excise tax on distilled spirits lowered by Congress. |
| First labor union in United States organized by Philadelphia shoemakers; suspended after a year, but reorganized on a permanent basis in 1794. |
| First iron furnace in the Pittsburgh district erected by George Anshutz. |
| Yellow fever epidemic in Philadelphia causes 4,000 deaths. |
| 1793 | Bank of Pennsylvania opens branches throughout State. 1794 Excise tax on distilled spirits again lowered by Congress. |
| Whiskey Insurrection quelled. 1797 First American frigate, the United States, launched at Philadelphia. |
| 1799 State capital removed from Philadelphia to Lancaster. |
| 1798 Fries Rebellion quelled by militia. |
| 1800 Connecticut relinquishes all claims to jurisdiction in the Wyoming Valley. |
| National Capital removed from Philadelphia to Washington. |
| 1802 | First law for free education enacted. |
| 1804 | First bank in western Pennsylvania established at Pittsburgh. |
| First bituminous coal shipped to eastern markets. Stage route to Pittsburgh opened.
|
| 1805 | Striking shoemakers in Philadelphia indicted for forming 'a combination and conspiracy to raise their wages.' |
| 1807 | First successful flint glass factory in America founded in Pittsburgh by Bakewell & Page. Commercial manufacture of oilcloths started in Philadelphia by John Dorsey. |
| 1808 | First sea-going steamboat arrives in Philadelphia from New York. 1811 First steamboat to operate on the Ohio and Mississippi launched at Pittsburgh. 1812 The State capital established in Harrisburg. |
| 1812 | Pennsylvania is asked for 4,000 volunteers to serve in war against Great Britain, declared June 18; Stephen Girard helps to finance war. First effective commercial use of anthracite made by White and Hazard at Falls of the Schuylkill. 1813 Delaware Bay blockaded by the British in March. Lieutenant Perry sent to Lake Erie in March with instructions to build a fleet; Perry's fleet captures British squadron on Lake Erie Sept. 10, 1814 General assembly votes extra pay to Pennsylvania militiamen and offers to lend the Federal Government $1,000,000. |
| 1819 | First savings bank in Pennsylvania founded. |
| 1820 | Population of State increases to 1,040,458. |
| 1828 | Workingmen's Party organized in Philadelphia. |
| 1830 | Commonwealth torn by factional struggles like the Anti-Masonic agitations. 1831 Baldwin Locomotive Works established in Philadelphia. 1835 The Anti-Masonic elements elect Joseph Ritner governor. 1836 Public use of gas has its inception in Philadelphia February 8. |
| 1837 | Anthracite first used in smelting ore at Mauch Chunk. |
| 1838 | A new State constitution, the third, is adopted by popular vote. |
| 1840 | Pennsylvania's population, doubled since the War of 1812, is 1,724,033. |
| 1851 | Financial crash, Aug. 1, caused by failure of the Bank of the United States of Pennsylvania. |
| 1842 | Legislature forbids use of State jails for fugitive slaves. |
| 1844 | Riots between Catholics and Native Americans occur in the Kensington section of Philadelphia in May and in the Southwark section July 5-7. |
| 1845 | Manufacture of steel rails begun at Danville. |
| Steam towboats introduced on Ohio River at Pittsburgh. |
| 1846 | Telegraphic communication between Harrisburg and Lancaster completed; first telegraph message over the Alleghenies sent in December. |
| Governor Shunk calls for volunteers May 16, to serve in war with Mexico. |
| 1848 | Pennsylvania elects first Whig governor, William Freame Johnston. |
| First miners' union organized. |
| 1849 | First strike of anthracite miners declared May 11. |
| 1851 | Christiana riot breaks out in Lancaster County over escaped slaves. |
| 1854 | The county of Philadelphia is merged with the city Feb. 2. |
| 1855 | Horsecars operated for first time in Philadelphia. |
| 1856 | First Republican Presidential convention held in Philadelphia June 7. |
| 1859 | First spouting petroleum well in history driven by E. L. Drake near Titusville. |
| National Union of Machinists and Blacksmiths and the Molders' International Union formed. |
| 1860 | State's population is 2,906,215. |
| 1861 | First Republican governor, Andrew Gregg Curtin, inaugurated. |
| Lincoln speaks at Independence Hall Feb. 22. |
| 25 regiments of Pennsylvania infantry mobilized after Lincoln's call for volunteers April 15; a Pennsylvania detachment is first to reach Washington, April 18. |
| 1862 | Conference of loyal governors held at old Logan House in Altoona, Sept. 24 |
| 1863 | Battle of Gettysburg July 1-3. |
| 1867 | First practical production of Bessemer steel in America is made at Steelton. |
| 1871 | First open-hearth method of steel production in Pennsylvania put in operation at Pittsburgh. |
| 1873 | Philadelphia banking house of Jay Cooke fails; money panic follows. |
| 1874 | Fourth State Constitution becomes effective Jan. 1. |
| 1876 | Philadelphia holds Centennial Exhibition; Alexander Graham Bell's new telephone exhibited. |
| 1877 | 26 workers killed or injured in Pittsburgh railroad strike. |
| 1880 | State's first elevated railroad built in Philadelphia. |
| State's population is 4,282,891. |
| 1881 | American Federation of Labor organized in Pittsburgh railroad strike. |
| 1887 | First U.S. Navy contract for American-made armor plate given to Bethlehem Iron Co. |
| 1889 | Johnstown flood occurs May 31. |
| 1891 | Serious labor troubles break out in various parts of State. |
| 1892 | 100 lives lost in June as dam at Spartansburg bursts. |
| Several lives lost and many injured in strike at Carnegie steel plant, Homestead. |
| 1897 | Labor riots in Luzerne County result in death of 20. |
| State capitol at Harrisburg destroyed by fire Feb. 2. |
| Pittsburgh fire causes loss of $3,000,000 May 3. |
| 1898 | Cornerstone of new State capitol laid Aug. 10. |
| 1900 | State's population is 6,302,115. |
| 1901 | Charles M. Schwab becomes president of United States Steel Corporation. |
| 1908 | Capitol graft exposed. |
| 1915 | Advanced types of social legislation effected. |
| 1920 | Pioneer radio station at Pittsburgh leads to the establishment of first permanent commercial broadcasting station in world. |
| 1923 | Licensed saloons are abolished. |
| 1926 | Sesquicentennial International Exposition held in Philadelphia. |
| 1927 | State Department of Revenue created. |
| Huge road-building program begun. |
| 1930 | State's population set at 9,631,350 by census. 132 Talbot law enacted, allotting $10,000,000 for unemployment relief. |
| 1933 | State appropriates $45,000,000 for needy. |
| 1935 | After 45 years Democrats again occupy capitol at Harrisburg with election of Governor George H. Earle and a majority in the lower house of legislature. |
| 1936 | At special session legislature appropriates huge sums for relief and levies emergency taxes. |
| Eastern and western sections of State swept by floods. |
| Democratic National Convention held in Philadelphia, renominates Franklin D. Roosevelt and John N. Garner. |
| 1937 | A $50,000,000 bond issue for flood control approved by the assembly. |
| 'Little Wagner Act' enacted June 1. |
| Widespread CIO strike against 'Little Steel' breaks out in June. |
| State celebrates 150th anniversary of Federal Constitution at Philadelphia. |
| 1938 | Arthur H. James, Republican, elected governor and James J. Davis, Republican, United States senator. |
| 1939 | Outbreak of war in Europe stimulates coal and steel industries. |
| 1940 | Republican National Convention held in Philadelphia nominates Wendell L. Willkie and Charles L. McNary. |
| Super-Highway opened Oct. 1. |
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