| EVENT | IMAGE | SOURCE |
| 8,000 BC | Last glacier recedes from western PA.... | John Harper, Chief, Subsurface Geology Section, DCNR, Pittsburgh, PA |
| 200 AD | the Aquanushioni | www.geocities.com/Athens/Oracle/4034/a54.html |
| 1753 | British Major George Washington, 22 | The Journal of Major George Washington:An Account of his First Official Mission, Made as Emissary from the Governor of Virginia to the Commandant of the French Forces on the Ohio, October 1753-January 1754. pp. 21-22. Published by Dominion Books, The University Press of Virginia | | | | | | |
| 1760 | Fort Pitt | Fort Pitt Museum, Pittsburgh, PA |
| 1762 | Wingenund, Munsee Indian prophet.... | Points in Time: Building a Life in Western Pennsylvania, editor, Paul Roberts, Western Pennsylvania Historical Society, 1996 |
| 1787 | University of Pittsburgh | University of Pittsburgh |
| 1791 | Whiskey Rebellion started in.... | Points in Time: Building a Life in Western Pennsylvania, editor, Paul Roberts, Western Pennsylvania Historical Society, 1996 |
| 1792 | 1st blast furnace in Pittsburgh | Report of Flood Commission Pittsburgh, PA, 1912, president, H.J. Heinz |
| 1793 | Beaver, once very abundant.... | Water, by Alice Outwater, 1996, Basic Books, p. 47 |
| 1794 | Canandaigua Treaty of 1794 | www.ratical.com/many_worlds/6Nations/TreatyRights.html#fn2 |
| 1797 | 1st glass factories | HJ Heinz Regional History Center, glass exhibit: "Shattered Notions", 1999 |
| 1804 | Charles Thaw, shipping merchant.... | Points in Time: Building a Life in Western Pennsylvania, editor, Paul Roberts, Western Pennsylvania Historical Society, 1996 |
| 1811 | The New Orleans, 1st steamboat | Report of Flood Commission Pittsburgh, PA, 1912, president, H.J. Heinz |
| 1818 | Botanist F. A. Michaux writes..... | From Coastal Wilderness to Fruited Plain , Cambridge University Press, 1994, Gordon G. Whitney, p. 82 |
| 1830 | In Jefferson County, 2,000,000 feet of white pine | www.geocities.com/Athens/Oracle/4034/ see "Articles" |
| 1830 | Conemaugh Salt Works ships out 500,000.... | Historic plaque at the riverside park in Saltsburg, PA |
| 1836 | Cornplanter | http://hawk.hama-med.ac.jp/dbk/cornplanter.html |
| 1837 | French traveler Michael Chevalier.... | Points in Time: Building a Life in Western Pennsylvania, editor, Paul Roberts, Western Pennsylvania Historical Society, 1996 |
| 1844 | First viable telegraph transmission | interview with Joel Tarr, Professor of History, Carnegie Mellon U. |
| 1859 | WorldÍs 1st oil well struck at Titusville | Drake Well Museum, Titusville, PA |
| 1865 | Maximum river discharge at Kittanning | Report of Flood Commission Pittsburgh, PA, 1912, president, H. J. Heinz |
| 1866 | An English financial reporter.... | http://wnyrails.railfan.net/jtn_home.htm |
| 1867 | Oil Creek during heyday of oil drilling | Mather's Historic Oil Regions of Western PA, 1895, Drake Oil Museum, Titusville, and The Destruction of FreshWater Fauna in Western PA, by Dr. A. E. Ortmann. Reprinted from Proceedings of the American Philosophical Society, Vol. XLVIII, No. 191, 1909 |
| 1869 | 150 timber rafts ran out of Red Bank Creek | www.geocities.com/Athens/Oracle/4034/a10.html |
| 1878 | "Unmentionable Rivers" Debate | "Headwater District of the Pittsburgh Corps of Engineers", USACOE, Dr. Leland R. Johnson, 1970's, pp. 118-131 |
| 1880 | Southern New York and northern PA.... | From Coastal Wilderness to Fruited Plain, Cambridge University Press, Gordon G. Whitney, 1994, p. 187-188 |
| 1882 | Kinzua RR Viaduct | http://sunrise.simplenet.com/KinzuaBridge.html |
| 1886 | 40% of the original forest | From Coastal Wilderness to Fruited Plain, Cambridge University Press, Gordon G. Whitney, 1994 |
| 1887 | ...vast areas of virgin white pine forest.... | The Cook Forest, by Anthony E. Cook, Falcon Press, 1997, p. 21 |
| 1889 | Johnstown Flood | www.ctcnet.net/jaha/pages/jfm.htm |
| 1891 | Greatest discharge at the mouth.... | Report of Flood Commission Pittsburgh, PA, 1912, president, H.J. Heinz |
| 1892 | ñRattlesnakeî Pete.... | Venango County Historical Museum, Oil City, PA, 1998. Barbara Pearlstein, curator |
| 1892 | Pinkertons arrive at Homestead Steel Works | from "Pittsburgh: The Story of an American City," 4th ed. Stephen Lorant |
| 1892 | Out of 60 million bison.... | Water, by Alice Outwater, 1996, Basic Books, p. 47 |
| 1895 | Over 140,000 acres of forest.... | From Coastal Wilderness to Fruited Plain, Cambridge University Press, 1994, Gordon G. Whitney, p. 190 |
| 1898 | Kaul and Hall Mill at Saint MaryÍs is | From Coastal Wilderness to Fruited Plain, Cambridge University Press, Gordon G. Whitney, 1994, p. 188 |
| 1900 | Pennsylvania accounts for over 60%.... | From Coastal Wilderness to Fruited Plain, Cambridge University Press, 1994, Gordon G. Whitney, p. 188 |
| 1903 | Extracted from Jefferson County.... | www.geocities.com/Athens/Oracle/4034/ see "Articles" |
| 1904 | Log rafts on the Allegheny | The Cook Forest, by Anthony E. Cook, Falcon Press, 1997, p. 23 |
| 1905 | Purity of Waters Act | A Geography of Pennsylvania, E. Willard Miller, ed. Chapter 4, Water Resources, by E. Willard Miller, Penn State Press, 1995 |
| 1906 | 62 iron and steel works | The American Steel Industry, 1850-1970, Kenneth Warren, University of Pittsburgh Press, 1988 |
| 1907 | March 15, 35.5' flood | Report of Flood Commission of Pittsburgh, PA, 1912, president, H.J. Heinz | |
| 1907 | 70 deaths in June due to typhoid fever | Typhoid Fever Statistics by CF Drake, May 30, 1930, City of Pgh |
| 1909 | "...the Allegheny [at Pittsburgh] is utterly polluted...." | "The Destruction of FreshWater Fauna in Western PA", Dr. A. E. Ortmann. Reprinted from Proceedings of the American Philosophical Society, Vol. XLVIII, No. 191, 1909 |
| 1912 | Fire ravaged forest landscape | Appendix 1, Part II-Detailed Descriptions of the Drainage Basin, Report of Flood Commission Pittsburgh, PA, 1912, president, H.J. Heinz, p. 14 |
| 1912 | Pittsburgh Flood Commission report | Report of Flood Commission of Pittsburgh, PA, 1912, president, H.J. Heinz |
| 1912 | Since 1806 the rivers at Pgh have crossed.... | Report of Flood Commission Pittsburgh, PA, 1912, president, H.J. Heinz |
| 1914 | Passenger pigeon officially extinct | Water, Basic Books, Alice Outwater, 1996, p. 47 |
| 1920 | Pennsylvania has .06% of its original forests.... | From Coastal Wilderness to Fruited Plain , Cambridge University Press, 1994, Gordon G. Whitney, p. 191 |
| 1923 | Allegheny National Forest established | Interview w/ Michael Koryak, USACOE, Pittsburgh Division, 1998 |
| 1928 | Commonwealth of PA takes title.... | The Cook Forest, by Anthony E. Cook, Falcon Press, 1997, p. 21 |
| 1936 | St. Patrick's Day Flood | Pittsburgh: The Story of an American City, Stefan Lorant, Doubleday and Co., 1964 |
| 1937 | Clean Streams Law | A Geography of Pennsylvania, E. Willard Miller, ed. Chapter 4, Water Resources, by E. Willard Miller, Penn State Press, 1995 |
| 1940 | Crooked Creek Reservoir built | USArmy Corps of Engineers, Pittsburgh District |
| 1950 | City of Pittsburgh population | US Census Bureau |
| 1960 | Allegheny County population peaks | US Census Bureau |
| 1964 | Flooding behind newly constructed Kinzua Dam | www.ratical.com/many_worlds/6Nations/TreatyRights.html#fn2 |
| 1974 | Woodcock Reservoir on Woodcock Creek | USArmy Corps of Engineers, Pittsburgh District |
| 1977 | OPEC's oil embargo... | PA Coal Association and PA Department of Environmental Protection's Ebensburg District office. |
| 1982 | Previously declared "biologically dead" | Interview with Michael Koryak, USArmy Corps of Engineers, Pittsburgh District |
| 1992 | 86 miles of Allegheny River enters National | Allegheny Watershed Network |
| 1995 | Pittsburgh drinking water.... | interview with the Director of Pittsburgh Water Authority |
| 1996 | 50 miles of Clarion River.... | Allegheny Watershed Network |
| 1996 | Pittsburgh Voyager begins on-river.... | Pittsburgh Voyager Project |
| 1997 | USGS implements NWQA | USGS |
| 1997 | River volume at Natrona Heights | USArmy Corps of Engineers, Pittsburgh District |