1800
July 10: Governor St. Clair declares the new county will be named Trumbull. It is named after Jonathan Trumbull, Jr.

August: Salt Spring Tragedy

1801
June: First supply of merchandise is brought to Warren.
June 6: Mail route between Pittsburgh and Warren is established.

October 31: Warren receives its first mail delivery.

1802
Dr. John W. Seeley establishes his medical practice in Howland.

1803
September 3: The First Baptist Church of Warren is organized.

November 18: The Presbyterian Church of Warren is organized.

1812
June 16: Trump of Fame, first newspaper issued in the Western Reserve, is published.

1816
October 4: The Trump of Fame is renamed Western Reserve Chronicle.

1819
Ashtabula and Trumbull turnpike constructed.

1833
November 1: Ira West Gardner hung for murder in Trumbull County's only public hanging.

1837
May: Pennsylvania and Ohio Canal established.

1838
An experiment to establish a steam saw and grist-mill attempted and failed.

1840
First attempt to establish a historical society.

1843
January 29: President William McKinley is born in Niles, Ohio.

1846
June: A large number of Warren buildings are destroyed by fire.

1848
February: First successful railroad is established.

1850
Warren Machine Company is established.

1861
Webb's Opera House is built in Warren.

1869
October: Dana's Music Institute opens.

1876
August: The Warren Tribune is first published.

1880
May 16: Second National Bank is established.

1884
Earl Derr Biggers, creator of Charlie Chan, is born in Warren, Ohio.

1890
Packard Electric Company is established.

1899
The first Packard Motor Car is built in Warren.

1900
Youngstown Sheet and Tube is established by George D. Wick and James A. Campbell.

1901
President William McKinley dies.

1911
Warren is the first city in the United States to light its streets with incandescent bulbs.

1925
July 10-25: Clarence Darrow, Kinsman native, is the Defense Attorney for the Scopes Monkey Trial.

1933
Earl Derr Biggers, creator of Charlie Chan, dies.

1937
May: Little Steel Strike. The strike focuses on Republic, Youngstown Sheet & Tube, Inland, and Bethlehem Steel and is a month long bloodbath. Six strikers are killed.

1947
William Murphy, Sr. builds the first television set in Warren. Trumbull County schools hold tours so students may watch WEWS Channel 5 test pattern.

1954
Kent State University begins holding classes at several locations throughout the Trumbull County area.

1970
Groundbreaking occurs for Kent State University's Trumbull Campus.

1977
September 19:  Youngstown Sheet and Tube closes its Campbell Works and begins laying off over 4,000 workers. 4,100 workers permanently lose their jobs.

1980
January:  U. S. Steel closes McDonald and Youngstown Works, idling 3,500 workers.
Jones and Laughlin Steel closes Brier Hill Works, idling 1,400 workers.

1990
Dec. 2-10:  Dr. Ronald A. Parise, native of Warren, OH, is a Payload Specialist on Space Shuttle flight STS-35.

1995
March 2-18:  Dr. Ronald A. Parise, native of Warren, OH, is a Payload Specialist on Space Shuttle flight STS-67.

1998
Niles, OH becomes home for Minor League Baseball team--Scrappers.