# Historical maps locators
Each Property Report for a Chicago-based address or PIN has a Historical maps locator feature which links the reader to 80 Acres maps, Sanborn fire insurance maps, Cook County tax maps (sometimes called Sidwell maps), Water Books, 1938 aerial photos, and CMAP aerial photos (1970-1995).
None of these maps are hosted on Chicago Cityscape but the locator will identify the correct page of the map databases and open the map file on the databases' respective hosts.
## Accessing the historical maps locators
1. In a Chicago-based Property Report, select "Historical maps locators" in the table of contents. The page will automatically scroll down to the Historical maps locators section.
2. Select the image for the map you want to see.
3. After selecting the image, a map will appear showing green boxes around the Property Report's location (indicated by a blue house icon). Select the green box that contains the location and then select the link inside the popup that appears.
4. A new web browser tab will open on the map database's host server and will show the map that represented by the shape of the green box you selected.
## About the maps
### 80 Acres maps
Each 80 Acres map shows 80 acres of Chicago and contains survey information including [house numbers](https://www.map-strategies.com/blog/2018/10/24/getting-the-building-address-you-want-in-chicago) and lot dimensions. They also show subdivisions. Also view the City of Chicago's 80 Acres [citywide interactive map](https://gisapps.cityofchicago.org/mapchicago/?config=acre).
These are hosted by the City of Chicago.
### Sanborn maps
Each Sanborn map shows Chicago buildings as they were in the late 1980s and/or early 1990s. These are hosted by the City of Chicago.
*See also: [[Property history]]* which highlights alternative ways to find Sanborn fire insurance maps, including from different periods, as well as historic aerial photos.
### Tax maps
Cook County tax maps (sometimes called Sidwell maps) show the boundaries and PIN for each parcel. They also show subdivision names. These are hosted by the City of Chicago for the 2021 tax year.
### 1938 aerial photos
The State of Illinois photographed the entire state from airplanes in the late 1930s; Cook County was flown in November 1938. The locator shows the center point of each photo - select a marker to download the scanned photo (JPEG or TIFF) from the Illinois State Geological Survey. A dashed orange square shows the approximate area covered by the photo nearest the property (each photo covers roughly 2.8 miles in each direction).
Some photo centers were never scanned and have no download; their markers say so.
*A 1938 aerial photo of Chicago's Southeast Side, downloaded from the 1938 aerial photos locator. The US Steel South Works site and the Calumet River are visible.*
### CMAP aerial photos (1970-1995)
The Northeastern Illinois Planning Commission (now CMAP, the Chicago Metropolitan Agency for Planning) photographed the region every five years from 1970 to 1995. The locator shows the tile grid - select the rectangle covering the property and choose a year to download a ZIP file containing a georeferenced TIFF (each file is 50-100 MB). Not every tile is available for every year; tiles that are mostly water were only photographed in 1970.
You can also browse the same photos on [CMAP's Imagery Explorer](https://experience.arcgis.com/experience/f2515ce87d39455d8c6608a4b11b6520/).
*A 1970 aerial photo of Chicago's Southeast Side from the CMAP aerials locator, when the steel mills along the lakefront were still operating.*
### Water Books
Chicago Water Books are historical records of the city's water distribution system, showing water main locations, sizes, and installation dates. These documents are organized by book number and provide valuable historical context for properties.
**What the books show:**
- Historical water main locations
- Pipe sizes and materials
- Installation dates
- Service connections
**How to use:**
The Property Report shows which Water Book(s) cover your property location as a simple list (no interactive map). Click any book number to view the PDF document hosted by the City of Chicago.
**Source:** City of Chicago Department of Water Management
## Collection service
Don't want to gather these files yourself? For a fee, Chicago Cityscape staff will collect every available historical map and aerial image of your property - Sanborn sheets, 80 Acres maps, tax maps, water books, and aerial photos from 1938 to today - and deliver them to you as one organized folder with a summary document. [Email us](mailto:
[email protected]?subject=Historical%20images%20collection%20request) with the property address, or read about our [professional services](https://www.chicagocityscape.com/professionalservices.php).
## Other resources
There are other resources that we are unable to integrate but may provide you with more vintages (years) of maps and aerial imagery.
- [Chicago Aerial Photographic Services collection](https://digital.library.uic.edu/browse/collection/29?limit=50&sort=_score) the UIC Richard J. Daley Library. These images are not georeferenced and thus we cannot put them in our maps.
# Related articles
- [[Water Books]] (explains why water books are useful for determining historic unit counts)
- [[Property history]] (includes information on how to access older versions of the Sanborn maps and find historic aerial photos)
- [[Demographic data]]
- [Finding historical Census data to determine unit count](https://www.stevencanplan.com/2023/03/determining-dwelling-unit-count-at-an-address-using-1950-census-records/)