This collection is arranged into several major subgroups. The first group is for the Holter Family and allied families. The second major group is for the Holter Family Enterprises. The remainder of the collection consists of records of numerous companies grouped together in categories, including Mining subgroups, Lumber and Timber subgroups, Agriculture subgroups, Real Estate and Investment subgroups, Mercantile subgroups, Oil subgroups, Utility and Transportation subgroups, and Miscellaneous subgroups. Within each subgroup the basic arrangement is alphabetical by the name of the company.

The Holter Family Subgroup of the collection contains correspondence and other materials relating to individual family members. Within this subgroup is a series of family correspondence, which contains letters written between various Holters. The correspondence between Anton M. Holter and his sons, primarily Norman, Edwin, and Aubrey, and the correspondence between the three brothers, provides invaluable information concerning the many facets of the family's business activities and investments. Therefore, researchers are encouraged to read this family correspondence regardless of the topic of interest.

The greatest value of the collection is its completeness and its century-long time span coverage. The materials serve to provide invaluable information on the Holter family; the family companies, particularly the A. M. Holter Hardware Company; the growth and development of Helena and vicinity; and the lumber, ranching, and mining industries in the Northwest. The only weakness in the collection is the lack of any meaningful materials documenting the political activities of the period.