The Enterprise Planing Mill is important under criterion A as an excellent example of a long-standing, small, independent business in the Eastside of Portland. It was a family-run business for its entire history, and remained in the same location for all but its last year of operation. It represents one of the many small industries which typified this district in the early 20th century. The mill is also one of the last existing buildings of its type in Portland: a small, early 20th century building which contained a planing mill (wood is smoothed, cut and fitted) and retaining a high degree of historic integrity. It is the sole extant planing mill building in the study area, and a survey of planing mills in Portland which operated at the same time as the Enterprise found no others which retain significant integrity. - NRHP, 2 March 2006