1894-96 Vintage US Maine Pinback / Button. 

Our research suggests this pin was created by the White & Hoag Co. as a promotional item for the Chicago Great Western Railway Co.  It was a regional line between St. Paul and Iowa and called the Minnesota and Northwestern Railroad.
 

Note: The Maine was a US Battleship that was blown up in the Havana Harbor on Feb 15th 1898, killing 260 men on board. According to our research, to this day they don't know for sure who did it.