I am trying to find out, on a state-by-state (city/county as well, if possible) basis, what the population makeup is based on ancestry/ethnicity (i.e. Polish). For example, "what percentage of the population of Illinois in 2020 was of Polish ancestry?"
However, I have only been able to find this data at a national level. I can see that sites such as statisticalatlas.com have the information I'm looking for and cite Census.gov as being where they got it. But I need to cite an official government source for what I'm doing and I haven't been able to find the exact census product which they are citing for state level data.
Can anyone help?