Also known as L-town, or Long-town, it is quite possibly the shit of the Front Range. The name comes from the notion that the men here are well-endowed.
"Long" - self-explanitory
"Mont" or "Mount" - Meaning phallic or penis
Thereby saying that those in Longmont are well endowed
Girl 1: I just hooked up with this guy from Longmont
Girl 2: How was it?
Girl 1: Dude, he was huge!!