The postcard collection contains commercial souvenir postcards of specific towns and also non-commercial photographs of farms, homes, scenes, families or individuals that were printed on postcard stock paper for mailing.

The majority of the postcard collection originated from Lawrence, Kansas, including the University of Kansas, and also from towns in Douglas County, Kansas including Baldwin, Eudora, Wellsville, Lecompton, and a few more. The remainder of the postcards are from towns and counties from the rest of the state of Kansas. There are several postcards from Kansas City, Missouri, as well as a few from other towns in Missouri and from Nebraska locations.

The "title" of the postcard is a description of the image on the front of the card in the Lawrence, University of Kansas, and Douglas County sub-series. The note describes additional details of the subject and also the names of the sender or receiver of the postcard or other details in the inscription. Not all of the details are described.

In the sub-series of "Other Kansas towns or counties including forts..." the "title" is the name of the town (or county). The subjects of the postcards are described in the notes either specifically or summarized.

Items from Douglas County are described in greater detail than postcards from other areas of the state of Kansas or other states. The inscription (if any) on the back of the postcard from sender to recipient is generally not described except for those regarding Douglas County or other historical information.

The date given on a folder was taken from the caption on the postcard, from the sender's inscription, or from the post mark stamped by the post office. Since some of the postcards do not have a caption, were not inscribed, or were not postmarked (or the postmark is illegible), the date given may only represent one postcard in the folder. The date is only provided for a reference and does not necessarily represent the dates of all of the postcards in the folder.

Hollmann frequently wrote in pencil in all capital letters on the back of the postcards with information about the town or scene depicted on the front. In some cases, he corrected misidentified information in the postcard caption or gave clarification.