I live in Moscow, Idaho and saw this guy early in the morning last week. It was about quarter sized if I recall. I've never seen one before and was in a hurry so I couldn't get a better picture, sorry.
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This looks like a black trapdoor spider (I'm guessing male by the size of the abdomen), check out the photos on the page I've linked below and see what you think - and this is a pretty good picture, usually the photos friends send me are far more blurry!