1659/60, Jan. 12. Baltimore County known to have been established by this date, when a writ was issued to county sheriff.
1661. County seat located at Old Baltimore on Bush River.
Site of "Old Baltimore" historical marker, Abingdon (Harford County), Maryland, June 2015. Photo by Sarah A. Hanks.
1683. Gunpowder Manor, a tract of land containing some 7,031 acres, surveyed for Charles Calvert, 3rd Lord Baltimore.
1691. County seat established at Gunpowder Town on east bank of Gunpowder River.
Gunpowder Manor (Long Green Valley) historical marker, Baldwin, Maryland, July 2015. Photo by Sarah A. Hanks.
1742, July 10. First Baptist church in Maryland established by Henry Sater at Chestnut Ridge, Baltimore County.
1752, June 4. John Eager Howard (1752-1827), Governor of Maryland, born at “Belvedere” in Baltimore County.
1760, Dec. 6. Charles Ridgely (1760-1829), Governor of Maryland, born near Towson.
1765. Mason-Dixon Line marked northern border with Pennsylvania.
1766, Feb. 24. Sons of Liberty organized in Baltimore County.
Northampton Furnace historical marker, Lutherville, Maryland, July 2015. Photo by Sarah A. Hanks.
1773. Harford County formed from eastern Baltimore County.
1776. William Hoffman's paper mill (the first in Maryland) on Great Gunpowder Falls manufactured paper for Continental Congress, and nearly all its watermarked paper currency during American Revolution.
1781, Sept. 11. Rochambeau's French troops camped at Whitemarsh en route to Yorktown.
1782, Aug. Rochambeau's troops, traveling north, recamped at Whitemarsh after Yorktown.
Whitemarsh historical marker, Whitemarsh, Maryland, May 2019. Photo by Sarah A. Hanks.
1791. Benjamin Banneker (1731-1806) of Baltimore County published first edition of Pennsylvania, Delaware, Maryland, and Virginia Almanack and Ephemeris....
Hampton National Historic Site, Towson, Maryland, January 2002. Photo by Diane F. Evartt.
1809. Union Manufacturing Company textile mills began operation at Oella.
1814, Sept. 12. British repulsed by local militia at Battle of North Point.
1816. Warren Manufacturing Company textile production started near Cockeysville.
1816. Construction begun on U.S. Arsenal at Pikesville.
1820. Joppa Iron Works opened.
Gunpowder Copper Works historical marker, Glen Arm, Maryland, July 2015. Photo by Sarah A. Hanks.
1828, Feb. 13. Baltimore & Susquehanna Railroad chartered.
1837. Carroll County created from Baltimore County.
1844. Locust Grove Iron Works started.
1849, Oct.-1850, Oct. Robert E. Lee supervised construction of Fort Carroll on Patapsco River.
1851, July 1. Baltimore City, as a governmental unit, separated from Baltimore County.
1851, Sept. 11. Edward Gorsuch of Baltimore County killed while trying to recapture fugitive slaves at Christiana, Pennsylvania.
1854, Feb. 13. Towson chosen as new county seat for Baltimore County.
1861, May 5. Union Gen. Benjamin F. Butler (1818-1893) occupied Relay with troops to guard Thomas Viaduct, only rail link from north to Washington, DC.
1861, May 27-28. Sitting on circuit, Chief Justice Roger Brooke Taney (1777-1864) called in vain for release of John Merryman (1824-1881) of Cockeysville.
1864, July. Union and Confederate troops skirmished at Govanstown.
Historic Courthouse, 400 Washington Ave., Towson, Maryland, March 2001. Photo by Diane F. Evartt.
1864, July 10. Confederate forces under Brig. Gen. Bradley T. Johnson entered Cockeysville.
1864, July 10. Confederate Major Harry Gilmor's Raid at Towson.
1864, July 11. Governor Augustus W. Bradford's home at Towson burnt by Confederate troops.
Ishmael Day House historical marker, Sunshine Ave., near Kingsville (Baltimore County), Maryland, May 2015. Photo by Sarah A. Hanks.
1879, Sept. 9-12. Timonium fair grounds opened.
1881. Loch Raven Dam constructed.
1885, July 12. Howard Cooper lynched at Towson.
1887. Pennsylvania Steel (Maryland Steel, 1891) built blast furnaces at Sparrows Point.
1887. Frederick Law Olmsted, Sr., designed summer retreat, Sudbrook Park, near Pikesville.
1888. Baltimore City annexed land from Baltimore County.
1894, May 26. Maryland Hunt Cup, a steeplechase race, first run.
1898. Grand National Steeplechase first run.
1909, March 8. William Ramsey lynched at Rosedale.
1915. State Normal School moved from Baltimore to Towson.
1916. Bethlehem Shipbuilding Corporation, part of Bethlehem Steel, purchased Sparrows Point.
1918. Baltimore annexed land from Baltimore County to expand.
1920, Nov. 15. Logan Field (1920-1945) (originally Dundalk Flying Field) dedicated.
1928. Glenn L. Martin Company moved aircraft plant from Ohio to Middle River, Baltimore County.
1935. State Normal School renamed Maryland State Teachers College (now Towson University).
1935, Sept. 10. Black students Lucille Scott and Margaret Williams denied admittance to Catonsville High School.
1935, Nov. Pan American flew Martin M-130 flying boat, China Clipper, on first scheduled air-mail flight to Orient.
1938. Oblate Sisters of Providence moved from Baltimore to Catonsville.
1938. Glenn L. Martin Company began construction of PBM Mariner, an armed flying boat used in U-boat patrols, nighttime raids, and rescues, made first flight.
1939, Feb. 18. Glenn L. Martin Company's PBM Mariner made first flight.
1940, Sept. 1. First PBM Mariners entered U.S. Navy's patrol service.
1940, Nov. Martin B-26 Marauder bomber underwent first tests.
1941, April-Sept. Bethlehem-Fairfield Shipyard produced first Liberty Ship, Patrick Henry, launched Sept. 27, 1941.
1943-1945. Logan Field closed as airfield and used as prisoner-of-war camp.
1955, Sept. Public school desegregation began in Baltimore County.
1956. I-83, Baltimore-Harrisburg Expressway opened.
1956. County Charter provided for County Council and County Executive.
Hoffberger Science Center, Goucher College, Towson, Maryland, August 2003. Photo by Diane F. Evartt.
1957. Catonsville Junior College and Essex Junior College founded.
1958-1962. Christian H. Kahl (Democrat), County Executive.
1960. Social Security Administration opened offices at Woodlawn.
1962, July. Baltimore Beltway (I-695) opened through Baltimore County, encircling Baltimore City.
1962, Dec. - 1966, Dec. Spiro T. Agnew (Republican), County Executive.
1963. Maryland State Teachers College at Towson reformed as Towson State College.
1963, July 4 & 7. Black and white clergy led protests against segregation of Gwynn Oak Amusement Park, Baltimore County; some 283 persons arrested.
1963, Aug. 28. County Executive Spiro T. Agnew negotiated settlement with owners of Gwynn Oak Amusement Park to end segregation.
1966. University of Maryland campus at Baltimore County opened.
1966, Dec. - 1974. Dale Anderson (Democrat), County Executive.
1967, Jan. 25 - 1969, Jan. 7. Spiro T. Agnew (1918-1996) of Baltimore County served as Governor of Maryland.
1968, May 17. Catonsville Nine, protesting against war in Vietnam, destroyed draft records at Selective Service offices in Catonsville.
1969, Jan. 20 - 1973, Oct. 10. Spiro T. Agnew (1918-1996) of Baltimore County served as U.S. Vice-President; resigned and pleaded nolo contendere to criminal charges of tax evasion.
1969, Oct. 5. Maryland Public Television first broadcasted from Owings Mills (channel 67).
1971. Dundalk Community College opened.
1974. Frederick L. Dewberry (Democrat), Acting County Executive.
1974-1978. Theodore G. Venetoulis (Democrat), County Executive.
1975, Sept. 20. Martin State Airport opened at Middle River.
1976. Towson State College given university status.
1978-1986. Donald P. Hutchinson (Democrat), County Executive.
1981, Aug. 12. White Marsh Mall opened.
1981, Sept. 17. Hunt Valley Mall opened.
1986-1990. Dennis F. Rasmussen (Democrat), County Executive.
Key Bridge over Patapsco River, Baltimore, Maryland, October 2000. Photo by Diane F. Evartt.
1990-1994. Roger B. Hayden (Republican), County Executive.
1991, Oct. McCormick & Company opened new headquarters in Sparks.
1992. MTA Light Rail connected Timonium with Glen Burnie.
1994, Dec. 2 - 2002, Dec. 2. C. A. Dutch Ruppersberger III (Democrat), County Executive.
1997. MTA Light Rail extended to Hunt Valley.
1997. Towson State University renamed Towson University.
2002, Dec. 2 - 2010, Dec. 6. James T. Smith, Jr. (Democrat), County Executive.
2004, March 2. Electronic voting system used during primary elections at polling places and for absentee ballots in all counties and Baltimore City.
Library, Community College of Baltimore County, Catonsville, Maryland, May 2019. Photo by Diane F. Evartt.
2010, Dec. 6 - 2018, May 10. Kevin B. Kamenetz (Democrat), County Executive.
2012, June. At Sparrows Point (Baltimore County), steelmaking operations ended after RG Steel declared bankruptcy.
2012, Aug. Michael Phelps of Baltimore County became the most decorated athlete in the history of the modern Olympic Games, winning his 18th gold medal for a total of 22 Olympic medals.
2016, Aug. Michael Phelps won his 23rd Olympic gold medal, his 28th medal overall.
2018, Sept.-Oct. Bloede Dam demolished. Built in 1907 on the Patapsco River between Baltimore and Howard counties, it was the world's first underwater hydroelectric plant.
2018, May 10-29. Frederick J. Homan, Acting County Executive
2018, May 29 - Dec. 3. Donald I. Mohler III (Democrat), County Executive.
2018, Oct. 2. McCormick & Company opened new headquarters in Hunt Valley.
2018, Dec. 3-. John A. Olszewski, Jr. (Democrat), County Executive.
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