New Buffalo is a city in Berrien County in the U.S. state of Michigan. The population was 1,708 during the 2020 census. The area around the …New Buffalo is a city in Berrien County in the U.S. state of Michigan. The population was 1,708 during the 2020 census. The area around the mouth of the Galien River was originally populated by Miami and Potawatomi peoples. Later, French missionaries visited the area on their search for the fabled Northwest Passage. The area remained sparsely populated, even as Michigan Territory was petitioning for statehood.