Higashihiroshima extends from the coast of the Seto Inland Sea to the hilly area in the foothills of the Chugoku Mountains, with a large difference in elevation.

Archaeologists have found evidence of continuous human settlement from the Japanese Paleolithic period, with the oldest remains of several dwellings dating back to 22,000 years ago.

During the Nara period, the ancient Sanyōdō highway connecting the Kinai region with Kyushu passed close to the north side of Saijō Station.

During the Muromachi period, the area was dominated by the Ouchi clan, who built Kagamiyama Castle, the ruins of which are a National Historic Site.

After the establishment of the Tokugawa Shogunate, the area was part of the holdings of Fukushima Masanori and later the Asano clan of Hiroshima Domain.

Other industries include semiconductors, automobile related parts/special equipment, shipbuilding, and brick making, as well as agriculture centered on rice, and commercial fishing.