| 1974 | April | Saijo Cho, Hachihonmatsu Cho, Shiwa Cho, and Takaya Cho merge into a city |
| May | Mayor Takenori is becomes the first mayor |  |
| July | City emblem decided |
| 1975 | January | City anthem decided |
| 1977 | June | City tree and city flower decided |
| 1978 | May | Mayor Sanuki becomes the second mayor |
| June | Citizens’ Charter adopted |
| 1979 | June | Higashihiroshima City becomes a Disability Welfare City |
| City Museum opens |
| 1980 | July | Sister city agreement concluded with Hiroshima Cho, Hokkaido |
| November | Good will city agreement concluded with Marilia City, Brazil |
| 1982 | April | Hiroshima University School of Engineering transferred |  |
| 1985 | April | The city’s 10th anniversary ceremony held |
| June | Peaceful and Nuclear-free City Higashihiroshima Declaration issued |
| 1986 | February | Higashihiroshima City Purification Center starts operation |
| April | Higashihiroshima City General Welfare Center opens |
| 1987 | March | Sanyo Expressway (Shiwa IC - Hiroshima Higashi IC) opens |  |
| 1988 | March | Sanyo Shinkansen Higashihiroshima Station opens |
| July | Sanyo Expressway (Saijo IC - Shiwa IC) opens |
| 1990 | April | Kamo Environmental Center starts operation |  |
| October | First Sake Festival held |
| November | Sanyo Expressway (Saijo IC - Kochi IC) opens |
| 1991 | April | Kindai University Faculty of Engineering transferred |
| 1992 | July | Higashihiroshima Sports Park Gymnasium opens |
| August | Population reaches 100,000 |
| Sun Square Higashi-Hiroshima opens |
| November | Boulevard opens |
| 1993 | April | Mitsujo Kinrin Park opens |
| Route 2 Saijo Bypass opens |
| October | Friendship city agreement concluded with Tokuyo City, China |
| 1994 | April | Central Library opens |
| October | October Asian Games held |
| 1995 | April | All schools of Hiroshima University transferred except for the Medical School |
| June | Higashihiroshima Sports Park Athletic Stadium opens |
| 1996 | March | KAMON Cable Television starts broadcasting |
| October | 51th National Sports Festival of Japan is held |
| 1997 | April | Hiroshima International PLAZA opens |
| 1998 | January | Former Kagamiyama Castle designated as a National Historic Site |
| April | Hiroshima International University opens |
| May | Mayor Ueda becomes the third mayor |
| Techno Town Higashihiroshima opens |
| 1999 | April | The city’s 25th anniversary ceremony held |
| 2000 | November | National Cultural Festival Hiroshima 2000 held |
| 2002 | April | Boulevard opens completely |
| October | Sports Recreation Festival Hiroshima 2002 held |
| 2004 | April | Hiroshima Prefectural Junior and Senior High School opens |
| 2005 | February | Kurose Cho, Fukutomi Cho, Toyosaka Cho, Kochi Cho, and Akitsu Cho merge |
| 2006 | April | Mayor Kurata becomes the fourth mayor |
| May | Tenmondai Square opens |
| 2007 | May | Higashihiroshima Sports Park Baseball Stadium opens |
| November | Higashihiroshima-Kure Expressway (Umaki IC - Kamiminaga IC) opens |
| 2008 | September | Roadside Station Kohan-no-sato Fukutomi opens |
| 2009 | October | Prefectural operated Fukutomi Dam starts operation |
| November | Tennis courts and a club house open in Higashihiroshima Sports Park |
| 2010 | March | Higashihiroshima-Kure Expressway (Kamiminaga IC - Takaya IC) opens |
| September | Fukutomi Park Golf Course opens |
| 2011 | October | FM Higashihiroshima starts broadcasting |
| December | The new Fire Department Headquarters completed |
| 2012 | April | Higashihiroshima-Kure Expressway (Kurose IC - Aga IC) opens |
| 2013 | January | New City Hall building completed |
| 2014 | May | The city’s 40th anniversary ceremony held |
| 2015 | March | Higashihiroshima-Kure Expressway opens completely |
| 2016 | April | Higahshihiroshima Arts & Culture Hall “Kurara” opens |
