Hiroshima Airport (IATA: HIJ) fields a fairly good selection of domestic flights as well as some from Seoul, Bangkok and various points in China. Flight time from Tokyo, the busiest route, is around 90 minutes.
The Sanyo Shinkansen from Osaka to Fukuoka (Hakata) runs down the coast of Hiroshima prefecture, stopping at all major cities including Hiroshima and Onomichi. Direct Nozomi trains from Tokyo take about four hours to reach Hiroshima and cost ¥18,500 one-way.
Okayama Prefecture lies to the east. Kurashiki with its beautiful and well-preserved historic district is easily accessible from Hiroshima Prefecture. Other cities in the prefecture include Okayama, which contains many museums, Korakuen Garden one of Japan's Top 3 gardens, and the Kibi Trail, among other things. The city of Takahashi is home to the famous Bitchu Matsuyama Castle, which is the highest castle in Japan, as well as one of Japan's remaining original castles.
Shimane Prefecture is located north of Hiroshima Prefecture. In Izumo you can find Izumo Shrine, the second most holy Shinto Shrine in the nation; it's quite an impressive site. The city of Matsue is famous for Matsue Castle, one of only twelve original castles left in Japan, Vogel Park, one of the largest greenhouses in the world, and the Lafcadio Hearn Residence. Shimane is also home to one of UNESCO's World Heritage Sites, Iwami Ginzan, in Oda.
Yamaguchi (prefecture) borders Hiroshima Prefecture to the west. In the city of Yamaguchi, you will find the beautiful Rurikoji Temple, Joieiji Temple, and memorial for Saint Francis Xavier. In Hagi, there are many cultural sites, such as the ruins of Hagi Castle, Hagi Castle Town, and the Hagi Uragami Museum which houses a large amount of famous Japanese Ukiyoe artwork. For nature lovers, Akiyoshidai is home to Akiyoshidai Plateau, the largest limestone plateau in Japan and the Akiyoshido Cave, the largest cave in Japan. Akiyoshidai is not so well known among foreign tourists however, it is a unique and and very worthwhile addition to one's travel itinerary.