1755, April 20. British Maj. Gen. Edward Braddock (1695-1755) and troops encamped at Rockville area.
1774, June 11. Hungerford Resolves call on colonists to stop trade with Great Britain and the West Indies.
1775, Dec. 31. Gen. Richard Montgomery (1738-1775) died leading American attack on Quebec.
1776. Montgomery County created from Frederick County, named for Revolutionary War Gen. Richard Montgomery (1738-1775).
1787. First Courthouse erected at Williamsburg (now Rockville).
1791, Dec. 19. Maryland ceded 36 square miles of Montgomery County land (Georgetown) for federal District of Columbia.
1794. Hyattstown Mill constructed.
1808. Brookeville incorporated.
1809. Rockville Academy chartered.
1809-1823. Nathan Loughborough (1772-1848) of Montgomery County served as U.S. Comptroller of the Treasury.
1814, Aug. 26-27. President James Madison, Attorney General Richard Rush, and other Cabinet members sought refuge at Brookeville, following British attack on Washington, DC.
1828-1848. Chesapeake and Ohio Canal constructed.
1830. Josiah Henson (1789-1883) from slavery on Isaac Riley's farm (North Bethesda) escaped to freedom in Canada.
1833. Monocacy Aquaduct at Dickerson, design and construction overseen by Benjamin Wright (1770-1842).
1833. Seneca Aquaduct opened at Seneca.
1840. Second Courthouse completed at Rockville.
1860. Rockville incorporated.
1860. Free county public school system established for white children.
1861-1864, Sept. Montgomery Blair (1813-1883) of Silver Spring served as U.S. Postmaster General.
1861, June-1862, March. Union Brig. Gen. Charles P. Stone's corps of observation at Poolesville.
1862, Sept. 5. Confederate cavalry brigades under Gen. Wade Hampton and Gen. Fitzhugh Lee camped around Barnesville.
1862, Sept. 8. Skirmishes at Poolesville and Hyattstown between Union and Confederate cavalry.
1862, Sept. 9. Skirmishes at Beallsville and Barnsville between Union and Confederate cavalry.
1862, Sept. 13. Union Gen. Winfield Scott Hancock's II Corps camped near Barnesville on route to Antietam.
1862, Oct. 10-12. Gen. J.E.B. Stuart's cavalry rode through Washington, Frederick and Montgomery counties during raid into Pennsylvania.
1863, June 26. Union Maj. Gen. Joseph Hooker's headquarters established at Poolesville during Gettysburg campaign.
1863, June 27-28. Union troops marched through Barnesville on route to Gettysburg.
1863, June 28. Confederate Gen. J.E.B. Stuart and his cavalry occupied Rockville on route to Gettysburg.
1863, June 28. Confederate Gen. Jubal Early's cavalry arrested Union supporters at Rockville.
1863. Fort Alexander, Fort Ripley, and Fort Franklin, protecting Washington, DC, waster system since 1861, were connected by earthworks and renamed Fort Summer at Bethesda.
1864, July 11-12. Confederate Gen. Jubal Early had his headquarters at Silver Spring.
1867. Poolesville incorporated.
1872. Segregated county public school system began.
1873. Metropolitan Branch of Baltimore & Ohio Railroad ran from Washington, DC, northwest through Montgomery County to Point of Rocks.
1878. Gaithersburg incorporated.
1880, July 24. John Diggs lynched in Montgomery County.
1888. Barnesville incorporated.
1890. Takoma Park incorporated.
1891. Third Courthouse built at Rockville.
1892. Laytonsville incorporated.
1892. Francis G. Newlands (1846-1917) developed Chevy Chase.
1894. Kensington incorporated.
1894, April 27. "Coxey's Army" encamped at Gaithersburg on route to Washington, DC.
1898. Garrett Park incorporated.
1899, Oct. 18-1915. Gaithersburg Latitude Observatory as part of International Polar Motion Service began to measure variations in latitude caused by earth's wobble on its solar axis.
1904. Glen Echo incorporated.
1906. Somerset incorporated.
1910. Chevy Chase Village incorporated.
1912, April 12. Clara Barton, founder of American Red Cross, died at her home in Glen Echo.
1916, May 19. Blair Lee III (1916-1985), Acting Governor of Maryland, born in Silver Spring.
1918. Washington Suburban Sanitary Commission created to improve water and sewer service in Montgomery and Prince George's counties.
1918. Town of Chevy Chase incorporated.
1924. Floods destroyed much of Chesapeake & Ohio Canal.
1927. Maryland-National Capital Park and Planning Commission formed for Montgomery and Prince George's counties.
1932. "Bonus army" of World War I veterens and their supporters, seeking advance payment of cash bonus, traveled through Maryland on route to Washington, DC.
Montgomery County Courthouse, 27 Courthouse Square, Rockville, Maryland, February 2002. Photo by Diane F. Evartt.
1937. Washington Grove incorporated.
1937. Montgomery County equalized pay for black and white teachers.
1938. Federal government began moving National Institutes of Health to site near Bethesda.
1938. Silver Spring Shopping Center opened.
1938, June. National Institutes of Health established in Bethesda.
1939, Feb. Chesapeake & Ohio Canal opened as national park.
1942, Aug. Naval Medical Center dedicated, Bethesda.
1946, Sept. Montgomery County Junior College (now Montgomery College) opened, first junior college in State.
1948. Montgomery became first Maryland county to adopt charter form of government ("home rule"), with a County Manager and County Council.
1949, Jan. 18. First County Council took office.
1949, Jan. 21-1953, Jan. 20. Dean Acheson (1893-1971) of Montgomery County served as U.S. Secretary of State.
1951. The Sea Around Us, by Rachel Carson (1907-1964) of Montgomery County, published.
1954. County public school system began to desegregate.
1958. Desegregation of county public school system completed.
1960, June 30. Sit-ins and picket lines challenged segregation policies at Glen Echo Park.
1961, March 4. Sargent Shriver of Montgomery County named first Peace Corps director.
1962. Baltimore City and Montgomery County adopted open accommodations.
1962. Silent Spring, by Rachel Carson (1907-1964) of Montgomery County, published.
1964, Aug. 16. Capital Beltway (I-495) opened, encircling Washington, DC, by passing through Maryland's Prince George's and Montgomery counties, and Virginia.
1965. Washington Suburban Transit Commission established for Montgomery and Prince George's counties.
1968. County adopted a County Executive and County Council form of government.
1968. Marshall W. Nirenberg (1927-2010), National Institutes of Health, won Nobel Prize in Medicine.
1968, July 19-20. Eunice Kennedy Shriver (1921-2009) of Montgomery County opened first International Special Olympics in Chicago.
1969, Jan. 21-1973, Sept. 3. William P. Rogers (1913-2001) of Montgomery County served as U.S. Secretary of State.
1970. First County Executive elected.
1970. Radiation Biology Laboratory, a Smithsonian bureau, moved from Washington, DC, to Rockville.
1970-1978. James P. Gleason (Republican), County Executive.
1970. Julius Axelrod (1912-2004), National Institutes of Health, won Nobel Prize in Medicine.
1971, Oct. 12. Dean Acheson, who served as U.S. Secretary of State, 1949-53, died at his farm home in Silver Spring.
1972. Christian B. Anfinsen (1916-1995), National Institutes of Health, won Nobel Prize in Medicine.
1972. Sargent Shriver of Montgomery County, Democratic Party candidate for U.S. Vice-President, ran with George McGovern.
1976. D. Carleton Gajdusek (1923-2008), National Institutes of Health, won Nobel Prize in Medicine.
1976. Washington Metro, rapid transit system for national capital area, opened to link stations in Maryland, Washington, DC, and Virginia.
1978, Feb. Silver Spring Metrorail Station opened.
1978-1986. Charles W. Gilchrist (Democrat), County Executive.
1982. Village of Chevy Chase, Section 3 incorporated.
1982. Village of Chevy Chase, Section 5 incorporated.
Montgomery County Judicial Center, 50 Maryland Ave., Rockville, Maryland, February 2002. Photo by Diane F. Evartt.
1984. Shady Grove Metrorail Station opened.
1985. Martin’s Additions incorporated.
1986-1990. Sidney Kramer (Democrat), County Executive.
1990-1994. Neal Potter (Democrat), County Executive.
1993. Chevy Chase View incorporated.
1994, Dec.-2006, Dec. 4. Douglas M. Duncan (Democrat), County Executive.
1996. North Chevy Chase incorporated.
1997. Unification of Takoma Park into Montgomery County.
1997. William D. Phillips (1948-), National Institute of Standards and Technology, won Nobel Prize in Physics.
1999. Gunter Blobel (1936-), Howard Hughes Medical Institute, won Nobel Prize in Medicine.
2000. Eric R. Kandel (1929-), Howard Hughes Medical Institute, won Nobel Prize in Medicine.
2002, Sept. 10. Electronic voting machines first used during primary elections in four counties (Allegany, Dorchester, Montgomery, Prince George's).
2004, March 2. Electronic voting system used during primary elections at polling places and for absentee ballots in all counties and Baltimore City.
2005. John L. (Jan) Hall (1934-), National Institute of Standards and Technology, won Nobel Prize in Physics.
2005, Sept. 29. John G. Roberts, Jr. (1955-) of Montgomery County began to serve as Chief Justice, U.S. Supreme Court.
2006, Dec. 4-. Isiah (Ike) Leggett (Democrat), County Executive.
2007. Mario R. Capecchi (1937-), Howard Hughes Medical Institute, won Nobel Prize in Medicine.
2008. Roger Y. Tsien (1952-), Howard Hughes Medical Institute, won Nobel Prize in Chemistry.
2009. Thomas A. Steitz (1940-), Howard Hughes Medical Institute, won Nobel Prize in Chemistry.
2009. Jack W. Szostak (1952-), Howard Hughes Medical Institute, won Nobel Prize in Medicine.
2011, Feb. 23. First segment of Intercounty Connector (MD Route 200), the State's first all-electronic toll road, opened for Montgomery and Prince George's counties. Covering seven miles, this segment links Gaithersburg with Olney.
2011, Nov. 22. Second segment of Intercounty Connector opened to traffic, linking Olney with Laurel with ten additional miles of highway.
2013, May 13. Takoma Park became first municipality in nation to lower its voting age to sixteen for City elections.
2014, Nov. 9. Intercounty Connector (Maryland Rte. 200) completed for Prince George's and Montgomery counties.
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