Census Day is April 1st! Census Forms are due. Fill out your census form. This is one of the shortest forms in US history. For those that do not return their form, Census takers will then visit homes door to door in April-July, to complete the forms. Stand Up and Be Counted! For more information on the 2010 Census please check out the Census 2010 website or call OU Libraries at (405) 325-4142.