Find more online: Indiana University - Census Maps
Census maps are filed by SuDoc call number in their own range of map cabinets in the Map Room (4th floor).
Some, but not all, can be found through the the online catalog.
Use the Monthly Catalog of U.S. Government Publications
(In print: in Reference on the 2nd floor of the library: Z1223 .A18, ONLINE FROM 1994-PRESENT)