Bo-Dunk is an adjective that is similar to bum fuck both phonetically and by meaning. Bo-dunk describes a very low-population town. Mostly these towns have a few general stores, perhaps a small supermarket, a post office and some quaint houses. The towns undoubtedly have at least 1 church because the inhabitants are generally right-wing christian folk.
Some people prefer to live in bo-dunk towns because of the simplicity and the neighborly attitude of the inhabitants. Others get a deep depression just driving past bo-dunk towns.
The town in Napoleon Dynamite could be described as a textbook bo-dunk town.
Person A: Hi!
Person B: Hey dude, what's the shig? How's life in the hell that is Dehesa.
Person A: Shut up, dude. Living in Dehesa isn't that bad.
Person B: Dehesa is a bo-dunk shithole. You guys don't even have a post office. All the people in the town collect ceramic cows and shit like that.
Person A: Yeah you're right. I hate it here. This place is only good for old people and people who need to dump a body.
Person B: True.dat