William Holmes Cookman (1867–1950) was an American architect who was a staff architect and engineer of the Pennsylvania Railroad from about 1894 to the 1930s. Cookman graduated from the University of Pennsylvania in 1887. He was listed in Philadelphia city directories as a salesman or an artist from 1887 to 1890, and from 1891 to 1893 as a draftsman. From 1894 through 1930 he was listed as an architect. He began working for the Pennsylvania Railroad by 1901.[1][2] He became a member of the Philadelphia Chapter of the American Institute of Architects in 1912.[3] Cookman was a member of the American Railway Engineering Association, and served on the Association's Standing Committee VI. Buildings in 1914.[4]