Apparently it's official name as of 1947 is Hoover Dam. Before that, it was Boulder Dam, since the original site to build was in Boulder Canyon. But between 1930 and 1932, it was Hoover Dam.

That's what happens when politics are involved. Is it Hoover Dam or Boulder Dam ...?

This topic brings back an interesting memory: In my workplace years ago, when something sounded bad, several people coined the term, "That's a Hoover" ...which came from the longer phrase, "that sucks like a Hoover".