Aizu Wakamatsu is a principal city of Aizu region, which is located in Fukushima prefecture. Fukushima has distinguished differences among its three regions, Hamadori, Nakadori and Aizu regions. These three regions were ruled separately before the creation of Fukushima prefecture in 1872. It is also separated by Ou mountains and Abukuma heights.
Aizu Wakamatsu, former Wakamatsu was the most populated city in Fukushima when the Fukushima prefecture was born but the second largest city, Fukushima was chosen as the prefectural capital due the central location and Fukushima was not involved in the civil war called Boshin war.
Aizu Wakamatsu was the place where the Boshin war took place and fierce battle was fought between the army of the new Japanese government and the former Tokugawa shogunate supporters Byakko-tai, a youth army of Aizu domain consisting sons of samurai who are 16-17 years old fought fiercely in Aizu Wakamatsu but finally surrendered at Iimori mountain.
Aizu Wakamatsu can be visited from Tokyo by Tohoku Shinkansen to Kooriyama and change to JR Ban-etsu line. Or if you are traveling to nearby Kitakata and want to enjoy the scenery, better to take Joetsu Shinkansen to Niigata and then change there to Ban-etsu line.