This tick is in the genus Ixodes, and I'm pretty sure it is a Deer Tick (Ixodes scapularis). Deer Ticks (also called Black-legged Ticks) are notorious for spreading Lyme disease. After finding several of these, I have found a few unengorged adults as well.
The photograph above is an adult female, while that below is an adult male. I found the adult female crawling up my pants just yesterday after walking our trails.