Milhous worked for the Federal Art Project in Philadelphia from the year 1935 until she stopped in 1940. She made a lot of posters to advertise the state of Pennsylvania. A lot of the art showed people and things from the Pennsylvania Dutch community. Milhous met Alice Dalgliesh and the two women would write books together. Milhous would make the art for the books. Milhous went to work for Charles Scribner's & Sons where Dalgliesh worked. Milhous started to write and make art for her own books, too.