The Ibsen A. (Ibsen Andreas) Nelsen papers (1930-2001) include the plans, drawings, contracts, photographs, clippings, slides, and microfiche from the buildings he designed.  They span from the early 1950s to 2000 documenting his career as an architect in Seattle.  Some of his more prominent designs include the Pacific Museum of Flight, the Stewart House and Inn at the Market in the Pike Place Market, Merrill Court townhouses, and Bond Hall, Arntzen Hall, the Northwest Environmental Studies Center on Western Washington University’s campus in Bellingham.

Among his personal papers are some biographical materials and articles written about Nelsen.  Also, there are papers documenting his civic activism, the writing and speeches he gave, and the clippings he collected that reflect his interests.  In addition, the collection includes his correspondence throughout his adult life.  The recipients include his family and well-known artists and architects Isamu Noguchi, Fred Bassetti, George Bartholick, Victor Steinbrueck, Mary Randlett, Morris Graves, and Tom Robbins.