We analyze patterns of genetic variation in extant human polymorphism data from the National Institute of Environmental Health Sciences single nucleotide polymorphism project to estimate human demographic parameters. We update our previous work by considering a larger data set (more genes and more populations) and by explicitly estimating the amount of putative admixture between modern humans and archaic human groups (e.g., Neandertals, Homo erectus, and Homo floresiensis). We find evidence for this ancient admixture in European, East Asian, and West African samples, suggesting that admixture between diverged hominin groups may be a general feature of recent human evolution.