1900 Census microfilms at Internet Archive

Reel 45. Apache, Cochise, Coconino, Gila, Graham, and Maricopa (part: Eds 23-25 and ED 26, sheets 1-10) Counties
Reel 46. Maricopa (cont'd: ED 26, sheet 11--end), Mohave, and Navajo (including Fort Apache) Counties; Moqui Indian Reservation
Reel 47. Pima, Pinal (including Fort Grant), Santa Cruz, Yavapai, and Yuma (part: EDs 71-72 and ED 73, sheets 1-5) Counties
Reel 48. Yuma County (cont'd: ED 73, sheet 6--end); Colorado River, Navajo, Fort Apache, Hualpai, and Supai Indian Reservations