A short history of Domestic Violence Awareness Month (DVAM). DVAM evolved from the "Day of Unity" in October 1981 conceived by the National Coalition Against Domestic Violence. The intent was to connect advocates across the nation who were working to end violence against women and their children. The Day of Unity soon became an entire week devoted to a range of activities conducted at the local, state, and national levels.
In October 1987, the first Domestic Violence Awareness Month was observed. That same year marks the initiation of the first national domestic violence toll-free hotline. In 1989 the U.S. Congress passed Public Law 101-112, designating October of that year as National Domestic Violence Awareness Month. Such legislation has passed every year since.
Original source can be found here.