x = read.table(textConnection("State Region
Vermont Northeast
Alabama South
Iowa Midwest
Nevada West
Oregon Northwest"), header=T)

levels(x$Region)
##[1] "Midwest"   "Northeast" "Northwest" "South"     "West"

## Some magic happens
levels(x$Region)
##[1] "Northeast" "South" "Midwest" "West" "Northwest"

x$Region = as.factor(x$Region, levels=c("Northeast", "South", "Midwest", "West", "Northwest")