In the high schools in my county, US history starts with the Jazz age and the unions throwing over the bosses.
I once substitute taught a US history class in a Southern California high school in which the students were beginning a unit on the 1920's. I believe one cannot properly teach about America in the 1920's without making at least a passing reference to the Bolshevik Revolution, which cast such a long shadow over world events in the years following 1917. However, not one student in this class had ever heard of the Bolshevik Revolution.