Here is a CSV based on the census:
https://github.com/kjhealy/us-county...s-by-state.csv
Many government agencies actually offer APIs or data dumps of the data available that they are responsible for. As an example, the Social Security Administration can give you dumps of all registered child names for the last 100+ years.
For the data that you want, you may want to check out the census website and see if they offer any of that available for free. I would imagine they do, since much research and many maps are based off of that data.