January

50th anniversary of Nixon signing the National Speed Limit Law on January 2, 1974.
75th anniversary of President Truman's Fair Deal speech on January 5, 1949
240th anniversary of the Treaty of Paris ratified on January 14, 1784
385th anniversary of the Fundamental Orders of Connecticut, considered the first colonial constitution, on January 14, 1639
55th anniversary of the USS Enterprise explosion on January 14, 1969
105th anniversary of the Great Molasses Flood on January 15, 1919
105th anniversary of the 18th Amendment ratified on January 16, 1919
105th anniversary of the Paris Peace Conference on January 18, 1919
80th anniversary of the Battle of Anzio starting on January 22, 1944
175th anniversary of Elizabeth Blackwell graduating with a medical degree, the first woman to do so, on January 23, 1849
100th anniversary of the Winter Olympics on January 25, 1924
75th anniversary of the Emmy Awards on January 25, 1949
80th anniversary of the Siege of Leningrad ended on January 27, 1944

February

140th anniversary of the Oxford English Dictionary, debuting on February 1, 1884
80th anniversary of the Battle of Kwajalein ending on February 3, 1944
235th anniversary of George Washington elected as the first President of the United States on February 4, 1789
60th anniversary of the Beatles arriving in New York City on February 7, 1964
120th anniversary of the Great Baltimore Fire on February 7, 1904
115th anniversary of the NAACP, founded on February 12, 1909
225th anniversary of the death of Captain Cook in Hawaii on February 14, 1799
95th anniversary of the St. Valentine's Day Massacre on February 14, 1929
245th anniversary of the Battle of Kettle Creek in Georgia on February 14, 1779
160th anniversary of the Battle of Olustee in Florida on February 20, 1864
205th anniversary of the Adams-Onís Treaty on February 22, 1819, giving the United States East and West Florida from Spain.
65th anniversary of the Daytona 500 on February 22, 1959
245th anniversary of the Battle of Vincennes in Indiana on February 25, 1779
160th anniversary of Andersonville, the POW camp, opening on February 27, 1864

March

95th anniversary of the Increased Penalities Act on March 2, 1929. The bill increased penalties for bootlegging.
145th anniversary of the United States Geological Survey, founded on March 3, 1879
160th anniversary of Ulysse S. Grant taking command of the U.S. Army on March 10, 1864
160th anniversary of the Red River Campaign in Louisiana, on March 10, 1864
170th anniversary of the Republican Party, founded on March 20, 1854
185th anniversary of O.K. enters national vernacular on March 23, 1839
250th anniversary of the Boston Port Act on March 25, 1774. The act was passed as a direct response to the Boston Tea Party and closed the Port of Boston
45th anniversary of the Three Mile Island incident on March 28, 1979
250th anniversary of the Coercive Acts on March 28, 1774. Another direct response to the Boston Tea Party
135th anniversary of the Eiffel Tower opening on March 31, 1889

April

235th anniversary of the first Speaker of the House, Frederick A.C. Muhlenberg, elected on April 1, 1789
75th anniversary of NATO, founded on April 4, 1949
50th anniversary of Hank Aaron breaking Babe Ruth's Home Run record on April 8, 1974
160th anniversary of the Fort Pillow Massacre, in Tennessee, on April 12, 1864
135th anniversary of the Oklahoma Land Rush on April 22, 1889
85th anniversary of the New York World's Fair opening on April 30, 1939

May

160th anniversary of the Battle of Spotsylvania, in Virginia, on May 8, 1864
110th anniversary of President Wilson declaring Mother's Day a national holiday on May 9, 1914
155th anniversary of the Transcontinental Railroad Completed on May 10, 1869
100th anniversary of John Edgar Hoover becoming the first FBI director on May 10, 1924
55th anniversary of the Battle of Hamburger Hill on May 11, 1969
220th anniversary of Lewis and Clark departing for their expedition on May 14, 1804
95th anniversary of the First Academy Awards on May 16, 1929
70th anniversary of Brown vs Board of Education on May 17, 1954
90th anniversary of Outlaws Bonnie and Clyde's death on May 23, 1934
100th anniversary of the Immigration Act, signed by President Coolidge on May 26, 1924
165th anniversary of Big Ben opening on May 31, 1859
135th anniversary of the Johnstown Flood on May 31, 1889
160th anniversary of the Battle of Cold Harbor, in Virginia, on May 31, 1864

June

245th anniversary of Benedict Arnold court-martialed on June 1, 1779
100th anniversary of the Indian Citizenship Act, signed by President Coolidge on June 2, 1924
80th anniversary of Operation Overlord on June 6, 1944
75th anniversary of the FBI releasing their Hollywood Blacklist on June 8, 1949
160th anniversary of the Battle of Petersburg, in Virginia on June 15, 1864
140th anniversary of The Switchback Railway, America's first roller coaster, opening on June 16, 1884
90th anniversary of the Indian Reorganization Act on June 18, 1934
80th anniversary of the Battle of the Philippine Sea on June 19, 1944
160th anniversary of the Battle of Cherbourg on June 19, 1864
80th anniversary of the GI Bill, signed by President Roosevelt on June 22, 1944
55th anniversary of the Stonewall Riots, in New York on June 28, 1969
110th anniversary of Archduke Ferdinand's assassination on June 28, 1914

July

60th anniversary of the Civil Rights Act on July 2, 1864
270th anniversary of the Battle of Fort Necessity, in Pennslyvania on July 3, 1754
140th anniversary of France gifting the Statue of Liberty to the United States on July 4, 1884
220th anniversary of the Burr and Hamilton Duel on July 11, 1804
235th anniversary of Bastille Day on July 14, 1789
55th anniversary of the Apollo 11 launch on July 16, 1969
255th anniversary of the Rosetta Stone, founded on July 19, 1799
55th anniversary of Man walking on the moon on July 20, 1969
55th anniversary of Apollo 11 returning on July 24, 1969

August

110th anniversary of the First World War, beginning on August 1, 1914
80th anniversary of Anne Frank captured on August 4, 1944
160th anniversary of the Battle of Mobile Bay, in Alabama, on August 5, 1864
110th anniversary of the electric traffic signal installed in Cleveland on August 5, 1914
50th anniversary of Nixon's resignation on August 8, 1974
90th anniversary of Alcatraz's first inmates arrive on August 11, 1934
60th anniversary of Woodstock on August 15, 1969
80th anniversary of Paris's liberation on August 19, 1944
230th anniversary of the Battle of Fallen Timbers, in Ohio, on August 20, 1794
65th anniversary of Hawaii becoming the 50th State on August 21, 1959
210th anniversary of Washington's portrait saved on August 24, 1814
85th anniversary of the first televised Major League Baseball game, against the Brooklyn Dodgers and the Cincinnati Reds on August 26, 1939

September

160th anniversary of Atlanta falling to Union forces on September 1, 1864
235th anniversary of the U.S. Treasury, founded on September 2, 1789
250th anniversary of the First Continental Congress on September 5, 1774
210th anniversary of the Battle of Lake Champlain, in New York on September 11, 1814
210th anniversary of Francis Scott Key writing his poem, the Star-Spangled Banner, on September 14, 1814
80th anniversary of Operation Stalemate (Battle of Peleliu) on September 15, 1944
75th anniversary of the Berlin Airlift ending on September 30, 1949

October

75th anniversary of the creation of East Germany on October 7, 1949
160th anniversary of the Battle of Darbytown Road, in Virginia, on October 13, 1864
160th anniversary of the Battle of Cedar Creek, in Virginia, on October 19, 1864
65th anniversary of the Guggenheim Museum opening on October 21, 1959
120th anniversary of the New York City subway opening on October 27, 1904
95th anniversary of "Black Tuesday," the Stock Market Crash on October 29, 1929
160th anniversary of Nevada becoming a State on October 31, 1864

November

70th anniversary of Ellis Island closing on November 12, 1954
165th anniversary of Darwin publishing "Origin of Species" on November 24, 1859
160th anniversary of the Sand Creek Massacre, in Colorado, on November 29, 1864
160th anniversary of the Battle of Franklin, in Tennessee, on November 30, 1864

December

165th anniversary of John Brown's execution on December 2, 1859
155th anniversary of Wyoming granting voting rights to women on December 10, 1869
80th anniversary of Glenn Miller disappearing on December 15, 1944
80th anniversary of the Battle of the Bulge, beginning on December 16, 1944
160th anniversary of Sherman reaching Savannah on December 21, 1864
210th anniversary of the Treaty of Ghent, signed on December 24, 1814
110th anniversary of the Christmas Truce on December 25, 1914

Please email me any anniversaries you think should be considered for this list or any corrections.