I filed on Jan 25, both fed and state. Fed was accepted on Jan 30 around 11a Central time, and state was accepted around 9p Central time. A friend of mine who filed on the 25th also but later that evening, her returns were accepted before mine. Only difference was I had to file long form and she was able to file short form. So I think the more complex, more credits/deductions take a little longer to process through.
