New Haven is a village in Gallatin County, Illinois, United States, along the Little Wabash River near its mouth at the Wabash River. Before the New Haven vicinity was settled, it was inhabited by multiple indigenous cultures. Some countryside southeast of the village near the Wabash was formerly the location of a village of a Late Woodland people known as the "Du…New Haven is a village in Gallatin County, Illinois, United States, along the Little Wabash River near its mouth at the Wabash River. Before the New Haven vicinity was settled, it was inhabited by multiple indigenous cultures. Some countryside southeast of the village near the Wabash was formerly the location of a village of a Late Woodland people known as the "Duffy Complex"; the location is now an archaeological site known as the Duffy site.