# 1970 block maps **URL:** \ **Category:** NHGIS\ **Created:** [September 20, 2024, 12:54am UTC](https://forum.ipums.org/t/1970-block-maps/6101 "2024-09-20T00:54:41Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![dkopf](https://avatars.discourse-cdn.com/v4/letter/d/aca169/32.png) [@dkopf](https://forum.ipums.org/u/dkopf)\ **Post date:** [September 20, 2024, 12:54am UTC](https://forum.ipums.org/t/1970-block-maps/6101/1 "2024-09-20T00:54:41Z")
Hi- I was using the 1970 block data for a project and it’s been great. I have been unable to locate any block maps for 1970 anywhere. Do you have a recommendations on how I can understand the block data I am analyzing? I am looking specifically at San Francisco County. ---
**Author:** ![JonathanSchroeder](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/jonathanschroeder/32/70_2.png) [@JonathanSchroeder](https://forum.ipums.org/u/JonathanSchroeder)\ **Post date:** [September 20, 2024, 4:11pm UTC](https://forum.ipums.org/t/1970-block-maps/6101/2 "2024-09-20T16:11:47Z")
We don’t know of an existing general source of digital maps of 1970 block boundaries. The Census Bureau published a series of print volumes of 1970 block data that include maps. Many university libraries have copies of those volumes. As it happens, though, we’ve already started on a project to create 1970 block boundary data for NHGIS, and we’re on track to publish our first release sometime this fall. Serendipitously, San Francisco is one of a handful of areas that we’ve already completed. We can share the data for San Francisco County in a preliminary file very soon; it just needs a couple finishing touches. I’ll report back here with a link when it’s ready, possibly early next week if not later today. ---
**Author:** ![dkopf](https://avatars.discourse-cdn.com/v4/letter/d/aca169/32.png) [@dkopf](https://forum.ipums.org/u/dkopf)\ **Post date:** [September 20, 2024, 4:13pm UTC](https://forum.ipums.org/t/1970-block-maps/6101/3 "2024-09-20T16:13:17Z")
Hi there! Thanks so much. How lucky for me! Thanks so much. ---
**Author:** ![JonathanSchroeder](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/jonathanschroeder/32/70_2.png) [@JonathanSchroeder](https://forum.ipums.org/u/JonathanSchroeder)\ **Post date:** [September 23, 2024, 9:40pm UTC](https://forum.ipums.org/t/1970-block-maps/6101/4 "2024-09-23T21:40:54Z")
You can now obtain our preliminary shapefile for 1970 blocks in San Francisco County at [https://secure-assets.ipums.org/nhgis/blocks-1970/block\_1970\_06075.zip](https://secure-assets.ipums.org/nhgis/blocks-1970/block_1970_06075.zip). You’ll be required to log in to your IPUMS account to access the file. If you have any trouble downloading or opening it, please let us know. ---
**Author:** ![dkopf](https://avatars.discourse-cdn.com/v4/letter/d/aca169/32.png) [@dkopf](https://forum.ipums.org/u/dkopf)\ **Post date:** [September 24, 2024, 6:27am UTC](https://forum.ipums.org/t/1970-block-maps/6101/5 "2024-09-24T06:27:52Z")
This is wonderful. Thank you so much. It did exactly what we needed. ---
**Author:** ![dkopf](https://avatars.discourse-cdn.com/v4/letter/d/aca169/32.png) [@dkopf](https://forum.ipums.org/u/dkopf)\ **Post date:** [November 4, 2024, 8:40pm UTC](https://forum.ipums.org/t/1970-block-maps/6101/6 "2024-11-04T20:40:19Z")
Hi there Jonathan. We were so excited about having the blocks data we are actually going to use it for comparing 1970 to 2020 block data. We were curious if you have a crosswalk of the blocks? Thanks! ---
**Author:** ![MPC\_vanriper](https://avatars.discourse-cdn.com/v4/letter/m/bc8723/32.png) [@MPC\_vanriper](https://forum.ipums.org/u/MPC_vanriper)\ **Post date:** [November 6, 2024, 8:29pm UTC](https://forum.ipums.org/t/1970-block-maps/6101/7 "2024-11-06T20:29:41Z")
We do not currently have a crosswalk from 1970 to 2020 census blocks. We have that as the deliverable for one of our grants, but we haven’t started on that work yet. Unfortunately, I don’t have a timeline for that work yet. Sincerely, Dave Van Riper ---
**Author:** ![dkopf](https://avatars.discourse-cdn.com/v4/letter/d/aca169/32.png) [@dkopf](https://forum.ipums.org/u/dkopf)\ **Post date:** [November 6, 2024, 9:31pm UTC](https://forum.ipums.org/t/1970-block-maps/6101/8 "2024-11-06T21:31:41Z")
Thanks for letting me know! And thanks for all your great work.