| 1896 | Los Angeles City Council accepts Griffith J. Griffith donation of 3,015 acres for Griffith Park (December 16). |
| 1912 | Griffith J. Griffith makes his offer of funds for a public observatory to Los Angeles City Council (December 12). |
| 1919 | Griffith J. Griffith dies (July 6); he leaves funds for construction of Observatory (and Greek Theatre) in his will. |
| 1933 | Groundbreaking occurs for the new Observatory building (June 20). |
| 1934 | Astronomers Monument, funded by the New Deal Public Works of Art Project (PWAP), is dedicated (November 24). |
| 1935 | The Phantom Empire, first of hundreds of movies filmed at Griffith Observatory, opens to public (February 23). |
| 1935 | Griffith Observatory is formally dedicated (May 14) and opens to the public (May 15). |
| 1935 | Observatory school field trip program – one of the first in the region – begins soon after opening (June). |
| * School programs run continuously from 1935-2001, bringing millions of students on field trips. |
| 1937 | Publication begins for the monthly Griffith Observer astronomy magazine (February). |
| 1937 | Griffith Observatory Astrorama sky chart is first sold to public; it has been produced continuously since. |
| 1942 | Military pilots train in the planetarium theater to navigate by the stars (January-February). |
| 1942 | Observatory is closed every evening because of World War II (February – May). |
| 1942 | 121st Coast Artillery members are garrisoned at the Observatory (starting in spring). |
| 1942-46 | Observatory is closed weekday evenings because of World War II (May 1942 – November 1946). |
| 1947 | Los Angeles Astronomical Society (LAAS) holds first meeting at the Observatory (October 14). |
| * LAAS members have met at the Observatory almost continuously since 1948. |
| 1948 | Premiere of A Trip to the Moon, the first planetarium show about space travel (June 28). |
| 1955 | Observatory is showcased – playing itself! – in the classic film Rebel Without a Cause (October 27). |
| 1958 | Dr. Dinsmore Alter retires after 23 years as first Observatory Director. |
| 1962 | Widely publicized “end of the world” prediction draws largest crowds ever seen to Observatory (February 4). |
| 1964 | Original Zeiss Mark II planetarium projector is replaced with Zeiss Mark IV projector (March 31). |
| 1966-67 | Apollo astronauts train in the planetarium theater to navigate by the stars (September 1966 – December 1967). |
| 1969 | Dr. Clarence Cleminshaw retires after 34 years of serving as either Assistant Director (1935-58) or Director (1958-69). |
| * During his service, Dr. Cleminshaw delivered over 7,700 planetarium lectures. |
| 1973 | Laserium premieres at Observatory (November 19); Laserium programs offered for 28 years (ending January 6, 2002). |
| 1974 | Dr. William Kaufman resigns after four years as the third Director (1970-74). |
| 1974 | Dr. E.C. Krupp becomes fourth Director (September); his service of 35+ years makes him the longest serving Director. |
| 1976 | Griffith Observatory is officially designated as Los Angeles Historic-Cultural Monument No. 168. |
| 1978 | Dr. Krupp and Debra and Harold Griffith officially incorporate Friends Of The Observatory (December 4). |
| 1981 | Observatory introduces use of first public and office computers in the City of Los Angeles (December). |
| 1984 | Copper domes of the Observatory cleaned (February 16, 1984 through November 8, 1985). |
| 1985 | Observatory celebrates its 50th birthday with large crowds, cake, balloons, and general revelry (May 14). |
| 1985 | Halley's Comet brings unprecedented crowds to the Observatory (November 8, 1985 – May 6, 1986). |
| * More people see Halley’s Comet at Griffith Observatory than anywhere else in the world. |
| 1989 | Observatory is featured on Rose Parade float (January 1). |
| 1990 | Los Angeles Board of Recreation and Park Commissioners approve Master Plan for the Observatory's future (July 5). |
| 1991 | Astronomers Monument restoration completed with public unveiling of new bronze armillary sphere (May 14). |
| 1994 | Huge crowds jam Observatory for live telescopic viewing of Comet Shoemaker-Levy 9 crashing into Jupiter (July 17). |
| * More people see Comet Shoemaker-Levy 9 impact scars at Observatory than anywhere else in the world. |
| 1996 | Observatory debuts first official website in the City of Los Angeles (September). |
| 1996 | Commissioners authorize hiring architects to begin design work for Observatory renovation and expansion (June 1). |
| 1997 | More people see Comet Hale-Bopp at Griffith Observatory than anywhere else on Earth (March 19 – May 4). |
| 2002 | Observatory closes to the public after 67 years of service for renovation and expansion (January 6). |
| 2002 | Governor, Mayor, and other dignitaries break ground for renovation project (October 30). |
| 2003 | Observatory shows more people (18,000) closest approach of Mars in 59,619 years than anywhere else (August 26-27). |
| 2006 | Observatory building and grounds reopen to the public after a $93 million makeover (November 2). |
| 2007 | Observatory debuts unprecedented 2.5 hour educational school program for 5th graders (March 8). |
| 2007 | Observatory hosts U.S. Conference of Mayors reception (June 22). |
| 2007 | Observatory eliminates reopening shuttle system and resumes direct public drive-up access (November 2). |
| 2008 | Observatory is named one of "Top Ten Places to See Before You Are Ten" by Travel and Leisure magazine. |
| 2009 | Observatory is featured on Rose Parade float (January 1). |
| 2009 | Debut of new planetarium show and many other programs mark the International Year of Astronomy (February 3). |
| 2009 | Cosmic Conjunction 2009 event features symphony on the lawn and original musical composition (October 4). |
