Mansions and Villains' Lairs in The Wild Wild West (1965)

I am making a list with at least one fictional mansion from literature, movies, and tv in every state in the USA.

And so far I have come up with fictional mansions for less than half the states, and I have noticed the western states have few fictional mansions so far.

Outside of large western cities like Dallas, Denver, Los Angeles, San Francisco, Seattle, etc. real life mansions are rather thinly spread in the western states, which may explain why I am having trouble thinking of fictional ones.

I can think of a few large, mansion-like, ranch houses like the Ponderosa ranch from Bonanza and the Spanish Bit ranch from Duel in the Sun.

But The Wild Wild West (1965) was far more glamorous than realistic, and influenced by James Bond and similar spy movies.

So I guess that it would have some implausibly luxurious mansions and impressive supervillain lairs in various locations in the west in some episodes.

So can anyone think of impressive mansions and supervillain lairs in the western states and territories from episodes of The Wild Wild West (1965)?