From the Census Bureau: Decennial Census P.L. 94-171 Redistricting Data

This is the data that will be used by state legislatures to redraw legislative districts this fall. 

- Click here for it.

Public Law 94-171 refers to the current law governing how the census bureau will do so.

- Click here for the relevant info.

It lives in section 141 of title 13, United States Code, which you can find here.