I had to share this fascinating visualization tool from NPR on the changing demographics of the United States (and each state) over the past 100 years.
Just keep in mind that the means of collecting race/ethnic data, and even the definitions of race have changed dramatically over the decades. For example, Census questions about Hispanic origin have not been asked consistently over time. Today's Census forms are self-reported, but prior census counts relied on a person's surname to determine Hispanic origin (so if your last name "sounded Hispanic" to a Census worker, you would be classified as such, whether your ancestors were Latino or not).
To link to the tool on NPR's website: