Trying to find the right reference number when you want to request documents from the Library and Archives Canada (LAC) collection can be a little daunting to a newcomer and sometimes even to the seasoned researcher. With titles such as Item ID number, archival reference no., former archival reference no., related control no., and other system control no., it can be difficult to know which number is required to place your request.
In general, the complete archival reference information that you need to request documents for consultation (or reproduction) can be found in the Reference field in the “Record Information – Brief” section of the online description for files, items and accessions, etc, available through our Collection Search database.
In the case where some information is missing from the reference field, it is always worth looking at the “Ordering and Viewing Options” section.

A sample record description in the Library and Archives Canada Collection Search database. Note the Reference field near the top of the page and the Conditions of access at the bottom of the page.
You will need to make note of the following information (if available), in the order indicated (1 to 6), in addition to the document title (located at the top of the description page):
- Archival Reference number – e.g., R112
- Former archival reference no. – e.g., RG, MG, LMS, MUS. It is also important to transcribe all of the information that follows the letter identification.
- An accession or BAN number – e.g., 2003-00459-9
- A volume or box number—without a volume or box number, nothing can be ordered.
- File no. (creator) or Item no. (creator)
- File title
It is important to note that the Item ID number found in Collection Search (formerly known as Mikan number) is not an accepted reference number. This number is a system number for Collection Search. It refers to the descriptive record, not the document itself. While useful for searching online, this number, unlike complete references, will likely change
That said, for the preceding example the following information would be needed for document retrieval:
RG24-C-1-c, Volume 32619, File no. 5902-33/47-302
Here are other examples of reference numbers and titles organized by media type.
Please note that the “Conditions of access” field, available under the header “Ordering and Viewing Options” also contains important information on access restrictions (identified by an access code) that apply to the records described and that indicate whether documents may or may not be freely consulted for research and reproduction purposes. For more information about access codes, please consult the following blog posts: Introduction and Part II.
Important considerations:
- Retrieval times for archival documents are between 36 and 48 hours as the documents are kept offsite and must be brought to 395 Wellington for viewing.
- Pay close attention to the restriction codes on the documents, which may require you to provide additional information if the files happen to be restricted.
- Some documents have already been microfilmed and are available for immediate viewing in the consultation room. If you see a record with a microfilm reel number, you can go directly to the microfilm room and pull the reel from the shelf for viewing.
- In addition, some microfilm reels starting with the letters C-, T- and H-, have been digitized through our collaboration with Canadiana and are available on the Héritage website.
If all else fails, feel free to ask the Orientation or Consultation staff for help to find the correct reference number, or complete the Ask Us a Question form.