I recall seeing blackface minstrel shows in the 1930s in, of all places, Santa Fe, NM (at the time predominantly Hispanic). One of the local clubs, I think Elks, put one on as a fund-raiser. Another was put on by the high school. There were others. I don't remember details, which probably means that they didn't mean anything much to me. The town (according to rumor circulating among us) had one Negro family, that we never saw. Al Jolson and his blackface rendition of "Mammy" was very popular, he was imitated by all the kids. Everything stopped and went quiet when Amos n' Andy came on, I don't recall any other show, radio or TV, that ever equaled its popularity. It parodied the neighbors we all knew.
I went into university, and was drafted into the army, so how long the shows persisted, I don't know.

The comment about being scared of the blackfaces reminded me that I was very afraid of clowns- at the circus, I hid my face and huddled against my parents while they performed. I still don't like them.