It's fairly low to the ground. Thanks!
From the general appearance, and from the opposite leaves (seen if you look carefully in the enlarged photo) I think this is Euoynmous europaeus (Wikipedia entry). Specimens I've seen can grow like a ground cover, similar to your picture, but they also get shrubby/woody. It is not native to the US. We'd need more details/pictures to be sure, but I'm guessing from how you worded the question these might not be available.