Most noteworthy in the collection are the various annual reports, ranging from 1872 to 1940, and employee timetables for the period 1887 to 1919.

The early annual reports give details on equipment and construction, as well as past accomplishments. The latter reports are primarily summarized accounting balance sheets. The remainder of the collection provides data on timetables, efforts by the GR&I to promote patronage by extolling the various recreational amenities in Northern Michigan and a small sampling of legal issues that face the railroad.

The collection provides unique insights into the operation of a turn-of-the century Michigan railroad. Since the GR&I operated under direct control of the PRR, however, most of the GR&I detailed records became part of the PRR records.