Norwegian Augustana Synod was a Lutheran church body in the United States from 1870 to 1890. The group's original name was the Norwegian-Danish Augustana Synod in America. The name was shorted in 1878.
The difference between the NAS and the Conference was the inclusion of the Book of Concord. The NAS wanted to include the whole book as confessional base. The Conference just wanted the three ecumenical creeds, Luther's Small Catechism and the Unaltered Augsburg Confession.
Nelson, E. Clifford, and Fevold, Eugene L. The Lutheran Church among Norwegian-Americans: a history of the Evangelical Lutheran Church (Minneapolis: Augsburg Publishing House, 1960)