The following text is taken from the NRHP Nomination Form to describe this building's significance:
In May 1908, the Roseburg Commercial Club and George Kohlhagen struck a deal. Kohlhagen would tear down Slocum's Hall and build a new two-story brick building; the entire second floor would be leased to the Commercial Club and constructed according to their wishes and needs. The first floor of the new building would have retail space for two stores. Construction began immediately. By October 1908, the first floor was ready for occupancy; Harth's Toggery opened for business in the south side of the building while the Hunsaker-Guest Grocery Company opened for business in the north side of the building. On January 11,1909 the "club rooms" on the second floor were complete and the Commercial Club moved in. The Umpqua Valley News reported that the space was "among the finest in the state containing ... all the latest and most modern conveniences" and included a wide entrance leading from Jackson Street, a reception room, a parlor, outer and inner office space, a meeting room, a billiards room with two pool tables, two card rooms equipped with the necessary paraphernalia to operate a first class card room, a bowling alley running the entire length of the building along the south wall, a cozy lunch room, a well-equipped kitchen, large closets, and toilets.
The Roseburg Commercial Club's "mission" was to determine what was best for the community and make it a good place to live and a profitable place to do business. It was active in attracting people and business to Roseburg and Douglas County through various activities. One of the first activities undertaken by the Commercial Club was the construction of a small pavilion near the Southern Pacific train depot where local agricultural produce and manufactured goods were displayed (this structure has been moved and significantly altered). In 1909, the Commercial Club published 40,000 booklets about the area to be distributed at Portland's Rose Festival and Seattle's Alaska-Yukon-Pacific Exposition and it organized and sponsored Roseburg's first Strawberry Festival which became a successful annual event, recognized as one of southern Oregon's most important events. In addition to the booklets, displays and festival, it also purchased newspaper advertisements throughout the Pacific Northwest and set up exhibits at several regional festivals and expositions.
The Commercial Club promoted and endorsed city and county improvements which would lead to further opportunities for the development of the business community and success in commerce. In 1909, it endorsed three legislative bills that would provide improved roads and highways in the state and encourage the city of Roseburg to install street lights. It actively recruited industry such as woolen mills and canneries and was instrumental in developing much of the fruit industry in the Umpqua Valley. It worked closely with area farmers and the local granges. In 1914, it worked to pass bonds for the building of a railroad from Roseburg to the coast. By the end of 1914, there were nearly 300 active members of the Commercial Club. Throughout its existence, the Commercial Club served as an "employment bureau" for the community. It was often involved in local labor issues.
In addition to supporting the business of the community, the Commercial Club played an active role in the social history of the community. For a period of time, the "club rooms" were opened to the general public once a month for a public reception. The Ladies Auxiliary of the club were actively involved in organizing social events associated with the Strawberry Festival, as well as local dances and receptions. The organization also co-sponsored events and activities with other civic groups.
As the nation became more involved in the war efforts of World War I, less energy was spent on developing commercial interests in Roseburg. By the end of 1918, the Commercial Club was nearly dormant. In January 1919, the Pacific Northwest Tourist Association visited Roseburg to promote tourism as a new direction in commercial development. Some long-time club members, along with several new club members, decided to bring the organization back to life. New officers were elected and on March 27,1919 a resolution was passed to change the name of the organization to the Roseburg Chamber of Commerce. As the group regained momentum with new leadership, a new name, and a new focus, they vacated the Kohlhagen Building and moved to new quarters.
In 1912, Kohlhagen added a second story to his meat market and tied the facades of the two buildings together creating the appearance of a single building. The original use of the second floor above his market is unknown; in 1920, this space was the residence and studio of photographer J.W. Hemus.
Following the departure of the Commercial Club, the "club rooms" were leased to Mrs. Charles S. Heinline in 1919 for the Heinline- Moore Musical Conservatory. In 1923, the music school expanded into the space above the meat market when Mr. Hemus left. Mrs. Heinline's music school occupied the second floor of the Kohlhagen Building until she moved to Portland in June 1937. In 1938, Naomi Scott's music school and H.A. Canady's law practice were located on the second floor of the building. In 1946, KRNR radio station moved into the rooms in the 1912 portion of the building. The former Commercial Club space was vacant until 1954 when the American Legion occupied the space. The spaces are now occupied in part by Tioga Resources, Inc. and Michael James Photography Studio.
The Kohlhagen Building is Roseburg's best preserved and earliest example of modem commercial architecture. Of its contemporary neighbors, it was the first to abandon the emphasis on strong stylistic ornamentation in favor a more stripped down, simplified appearance. Although the pressed tin cornices on the front facade were stylistic carry-overs from the Italianate style, the building's windows proportions and spacing, as well as the flat wall surfaces, are clearly related to the early 20th century Commercial Style. The building was probably the first in Roseburg to use pressed brick in a color other than red, setting a trend that resulted in several newer buildings constructed in the 1910s and 1920s. The building's style and construction method do not specifically copy any high style examples of early Chicago School styles but clearly illustrate the movement into the 20th century. The architect is unknown. A contractor named Patterson was responsible for the construction of the 1906 portion of the building; it is possible that Kohlhagen engaged him to construct the 1908 and/or the 1912 portions of the building as well.
In August 1959, an explosion known locally as "the Blast" leveled five city blocks near the intersections of Pine and Oak Streets in downtown Roseburg. Many of the downtown buildings sustained extensive damage; several had to be demolished. The epicenter of "the Blast" was approximately three blocks northwest of the Kohlhagen Building which sustained only moderate damage (in part because it was protected by the taller, five-story hotel building to its north). The explosion occurred at a time when remodeling older buildings in response to Urban Renewal was popular. While the destruction provided many building owners with the opportunity to modernize their buildings while repairing the damage, it resulted in the loss of much historic fabric on several historic buildings. Although most of Roseburg's downtown buildings were built within about twenty years of the Kohlhagen Building, few have retained their significant historic features.