Fillmore, IowaFillmore is an unincorporated community in Dubuque [County, Iowa|Dubuque County], Iowa, United States. The community is located along U.S. Route 151, east-northeast of Cascade.HistoryFillmore's population was 30 in 1887, and was 115 in 1902. The population was 20 in 1940.EducationResidents are zoned to the Western [Dubuque Community School District]. They are assigned to Cascade Elementary School and Cascade Junior/Senior High School, both in Cascade.