​Records at the Archives are maintained according to the state agency or local government that created them. Thus, records of the Transportation Department are maintained as one group and records of Multnomah County are maintained as another group. Usually, records are maintained in the order set by the agency when the records were created. 

Finding aids reflect this system. For instance, the finding aid for the Transportation Department lists and describes all records for that agency. Within the finding aid, records are described to the record series level. A record series is a set of records maintained together because of function, filing system, or other commonality (e.g., probate case files, administrative correspondence). In some cases, folder listings or indexes provide detailed descriptions of the records.

Finding aids are in binders located to the right of the reference desk. Many state agency finding aids have these basic components:

Agency history or over​view:​ A summary of an agency's statutory responsibility, mission, structure, function and programs from its creation to present or to its dissolution.

Scope​ and content notes​:​ Overview of the record group that summarizes the major types of records, date spans and size and highlights noteworthy records.

Record series list​: Alphabetical listing of each record series title in the group. Useful for quick scans when looking for records.

Record series descriptions​​: Date spans, size, arrangement, types of records and topics included in each record series.

Additional folder listings or indexes​: Lists or indexes generated by the agency or by an archivist in the course of conducting an inventory of the records. They provide more information than is available in the record series description.

Separated mater​ial lists​: Descriptions of photographs, maps, audio or video tapes, film, or other media separated from the general records to preserve them or because they don't fit in a standard archives box. (see example in Water Resources Desert Land Board Records​)

Many finding aids are adapted for the web and appear as state agency records guides. The guides have some advantages over the printed finding aids, including features such as image slide shows and web links. 

Finding aids with black binders contain legislative bill tracings dating from 1931 to the present. Find online Legislative Bill Tracings Tracings dating from 1981.

Finding aids with yellow binders contain listings of county records held by the Archives. Counties are not required to transfer records to the Archives. Find county records online in the Oregon Historical County Records Guide​. ​​​ ​​​​​