An excellent brief article.
An example:
On the Federal Housing Administration’s overtly racist policies in the 1930s, ’40s and ’50s
The second policy, which was probably even more effective in segregating metropolitan areas, was the Federal Housing Administration, which financed mass production builders of subdivisions starting in the ’30s and then going on to the ’40s and ’50s in which those mass production builders, places like Levittown [New York] for example, and Nassau County in New York and in every metropolitan area in the country, the Federal Housing Administration gave builders like Levitt concessionary loans through banks because they guaranteed loans at lower interest rates for banks that the developers could use to build these subdivisions on the condition that no homes in those subdivisions be sold to African-Americans.