loc.gov APIwww.loc.gov ↗
Query the LOC Sanborn Fire Insurance Maps collection by city and state. Returns sheet metadata, dates, item IDs, and high-resolution IIIF image URLs.
curl -X GET 'https://api.parse.bot/scraper/5bef1205-8db9-4d82-a034-aef5571a537e/list_sanborn_sheets' \ -H 'X-API-Key: $PARSE_API_KEY'
List Sanborn fire insurance map sheets filtered by location. Returns paginated results from the Library of Congress Sanborn Maps collection with metadata and highest-resolution IIIF image URLs for each sheet.
| Param | Type | Description |
|---|---|---|
| page | integer | Page number for pagination. Must be a positive integer. |
| state | string | State name to filter maps by (e.g. 'california', 'massachusetts'). Combined with location for more precise filtering. |
| location | string | City name to filter maps by (e.g. 'san francisco', 'boston', 'new york'). Used as a location facet filter. |
| per_page | integer | Number of results per page. Must be between 1 and 150. |
{
"type": "object",
"fields": {
"page": "integer current page number",
"pages": "integer total number of pages",
"total": "integer total number of matching sheets",
"sheets": "array of sheet objects with title, date, item_id, item_url, image_url, resource_url, and number_of_files",
"per_page": "integer results per page"
},
"sample": {
"page": 1,
"pages": 1,
"total": 8,
"sheets": [
{
"date": "1887-09",
"title": "Sanborn Fire Insurance Map from San Francisco, San Francisco County, California.",
"item_id": "sanborn00813_001",
"item_url": "https://www.loc.gov/item/sanborn00813_001/",
"image_url": "https://tile.loc.gov/image-services/iiif/service:gmd:gmd436m:g4364m:g4364sm:g4364sm_g008131887:00813_1887-0001/full/full/0/default.jpg",
"resource_url": "https://www.loc.gov/resource/g4364sm.g4364sm_g008131887/",
"number_of_files": 1
}
],
"per_page": 100
}
}About the loc.gov API
The Library of Congress Sanborn Maps API exposes 1 endpoint — list_sanborn_sheets — that returns paginated metadata for historical Sanborn Fire Insurance Map sheets from the LOC collection. Each result includes a title, date, item ID, detail URL, resource URL, file count, and the highest-resolution IIIF image URL available for that sheet. Filters for city and state let you narrow results to a specific geographic area.
What the API Returns
The list_sanborn_sheets endpoint queries the Library of Congress Sanborn Fire Insurance Maps collection and returns structured metadata for each matching map sheet. Each object in the sheets array contains: title (the sheet's descriptive title), date (publication or survey date), item_id (the LOC identifier), item_url (link to the LOC catalog record), image_url (highest-resolution IIIF image available), resource_url (the resource endpoint for the item), and number_of_files (how many image files exist for that sheet).
Filtering and Pagination
Results can be filtered by location (city name, e.g. 'boston' or 'new york') and state (e.g. 'massachusetts' or 'california'). Both filters can be combined to narrow to a specific city within a state. The per_page parameter accepts values between 1 and 150, and page controls which result page is returned. The response includes total (total matching sheets), pages (total pages), page (current page), and per_page alongside the sheets array.
Coverage and Data Source
Sanborn Fire Insurance Maps were produced from the 1860s through the mid-20th century, primarily covering urban areas in the United States. The LOC digitized collection holds tens of thousands of sheets across hundreds of cities and towns. Not every city or time period is equally represented — coverage depends on what LOC has digitized and made publicly accessible. The number_of_files field indicates how many image files are associated with a given sheet, which is useful for identifying multi-page or multi-segment entries.
- Retrieve all Sanborn map sheets for a specific city to support historical urban research.
- Download high-resolution IIIF images using
image_urlfor digitization or archival projects. - Identify building footprints and land use patterns in a historical neighborhood using sheet metadata.
- Build a geocoded index of LOC Sanborn sheets by combining
locationfilter results with GIS tools. - Check
dateandnumber_of_filesfields to find the most complete map coverage for a target city. - Automate discovery of map item IDs (
item_id) to batch-fetch LOC catalog records for historical property research.
| Tier | Price | Credits/month | Rate limit |
|---|---|---|---|
| Free | $0/mo | 100 | 5 req/min |
| Hobby | $30/mo | 1,000 | 20 req/min |
| Developer | $100/mo | 5,000 | 250 req/min |
One credit = one API call regardless of which marketplace API you call. Exceeding the rate limit returns a 429 response. Authenticate with the X-API-Key header.
Does the Library of Congress have an official developer API for its collections?+
What does `list_sanborn_sheets` return for each map sheet?+
sheets array includes title, date, item_id, item_url, image_url (highest-resolution IIIF image URL), resource_url, and number_of_files. The image_url field resolves to the best available resolution for that sheet, so it can be used directly for download or display.How complete is the geographic coverage across U.S. cities?+
total field in any filtered query shows exactly how many sheets LOC holds for that location. Using state alone (without location) will return all digitized sheets statewide.Can I filter by date range or map scale?+
location (city) and state, with pagination via page and per_page. Date and scale filtering are not exposed as parameters. You can fork this API on Parse and revise it to add date-range filtering against the LOC collection's available facets.Does the API return full map imagery or only metadata?+
image_url pointing to the highest-resolution IIIF image for each sheet. Actual image binary delivery is handled by the LOC IIIF image service at the URL provided — the API does not proxy or return raw image data itself.