United won all four of their games in the month, surging to second in the table behind Oldham.
The Latics won two games and drew two, but still hold on to the top spot in the table ahead of Scunthorpe thanks to better goal difference.
Millwall have also won all four of their games, as have Leeds.
The former Scunthorpe defender Alan Knill is nominated in League Two, his Bury side are joint top of the division.
The winners will be announced on Thursday afternoon.