add racial/ethnicity data by county
You seem to break down county population in numerous ways, but not by race/ethnicity. An odd omission.
Can you be more clear about what you're looking at/for? For example, here's a link to the Race & Ethnicity chart for Cook County, IL: https://censusreporter.org/profiles/05000US17031-cook-county-il/#race
That kind of chart is on every Census Reporter profile page, including all county pages.