Iwanuma Station is served by the Tōhoku Main Line, and is located 334.2 rail kilometers from the official starting point of the line at Tokyo Station. It is also served by the Jōban Line, and is 343.1 rail kilometers from the starting point of that line Nippori Station in Tokyo.
Iwanuma Station opened on December 15, 1887, on the Tōhoku Main Line. The Joban Line opened on November 10, 1897. The station was absorbed into the JR East network upon the privatization of the Japanese National Railways (JNR) on April 1, 1987. A new station building was completed in June 1998.