Nihonmatsu Castle (二本松城, Nihonmatsu-jō) is a Japanese castle located in what is now the city of Nihonmatsu, northern Fukushima Prefecture, Japan. Throughout most of the Edo period, Nihonmatsu Castle was home to the Niwa clan, daimyō of Nihonmatsu Domain. The castle was also known as "Kasumi-ga-jō" (霞ヶ城) or "Shirahata-jō" (白旗城). The castle is one of the 100 Fine Castles of Japan, and in 2007 was designated a National Historic Site.