Does anyone know the origin of the word, "Bumpkin?"
I'm trying to find where it comes from, and date of coinage.
Thank you in advance for your help.

AHD has some interesting comments but for best results, try wordorigins.org.

Word-detective has a bit more, and the 1828 Noah Webster's already had it listed.

"Any bumpkin would surely prefer this etymology to the suggestion that bumpkin is a derivative of bum, “the rear end.”"

heh. interestingly (or not), OED2 has three(3) disparate senses for bumkin, :
1) [[f. BOOM n. + -KIN; possibly the Du. boomken may formerly have been used in this special sense. The spelling bumpkin is now more usual.] ‘A short boom projecting from each bow of a ship, to extend the lower edge of the foresail to windward.’
2) a vessel for carrying water
3) [fr. bum + -kin] ‘A burlesque term for the posteriors.’ [quotes per OED2]

this seems to add some backstory to those AHD comments!

Thanks to all for responding so quickly.
I am in awe of your expertise.

I really appreciate the references too, thanks.

"possibly the Du. boomken may formerly have been used in this special sense. The spelling bumpkin is now more usual.] ‘A short boom projecting from each bow of a ship, to extend the lower edge of the foresail to windward.’"

May this DU. person add the comment that the word 'boomken'is Dutch for 'small tree' up till this day and 'boom' = 'tree'.
So the wood connection also to vessel is clear.