Marion, INDIANA - Court House:  Marion is a city in Grant County, Indiana, United States. The population was 29,948 as of the 2010 United States Census. The city is the county seat of Grant County.  It is named for Francis Marion, a Brigadier General from South Carolina in the American Revolutionary War.  Grant County is a county in central Indiana in the United States Midwest. At the time of the 2010 census, the population was 70,061.  This Undivided Back Era (1901-07) postcard is in good condition.