The building permits themselves are recorded in ledger books. To use the ledger books, you need to return to the Chicago Building Permits Collection home page, then select Chicago Building Permit Ledgers.
From that page you will again see a list of digitized microfilm reels, and you'll need to select the correct reel. When you're at this screen, you will already know the address you're looking for, and you will have noted at least two things from a card in the Street Index:
The date of the permit
The permit number
You may also have gotten a reference to a specific book, such as "W 35" and a page number, such as "427".
About the Ledger Book List
Each reel can contain two or three separate ledger books. Read the reel titles carefully to see which books appear on that reel.
Ledger books may be named with letters or numbers. Some books may not have either.
Each ledger book title will always include the span of permit issue dates covered in the book.
Most ledger book titles will divide the city up into regions such as North, South, West, etc. They may also cite areas that were recently annexed to Chicago, such as Lakeview or Hyde Park.
About the City Regions
We don't know the exact dividing lines between the city regions used for these books. Sometimes you will have a street address that is near a dividing line, and you may have to check more than one ledger book for your permit.
Sometimes permits were mistakenly recorded in the wrong ledger book. If you don't find a permit where you expect to see it, it is worth looking in a different ledger that covers the same time period. You are more likely to need to check multiple ledgers for permits issued 1920-1925 and 1939-1940.
If you recorded a book citation from the index card such as "W 35", that will translate to the title Book 35, West: Jun 12, 1925 - Jun 14, 1926.
Navigating the Ledger Books
Note whether the book you need is the first or second book on the reel. That will tell you about how far you need to scroll through the reel.
Use the date of the permit as your guide for scrolling. The permits are entered into the ledger books in date order, so that will tell you if you're getting close to the permit you're looking for.
The permit numbers can also be a guide, but they are not as dependable as the dates. The city started the permit numbers over again at #1 multiple times, and the permit numbers are not always in exact order.
If you noted a page number from the index card, note that it is the page number that appears in the microfilm image. It is not the page number that the Digital Reel system shows you as you navigate through the reel.
In an example from the Street Index, we found an index card for 2509 N. Laramie, issued on March 6, 1926 that was cited as being on page 427 of book "W 35".
Here is the image of Book 35, West: Jun 12, 1925 - Jun 14, 1926 showing page numbers 426 and 427. The page numbers are stamped at the upper left and upper right corners of the pages and are often hard to see. In this case, these pages appear on page 217 of the reel. The area where the permit appears is highlighted on the image.
Use the Zoom In or Scissors tools to see the individual permit more clearly.
Ledger Book Formats: Pre and Post 1912
The ledger books changed formats during 1912-1913. The older books look more like spreadsheets, and record less detail. The newer books look like forms, and include more information. The next two sections of this guide provide detail on how to interpret these two formats of ledgers.