Bylas is an unincorporated community and census-designated place in Graham County, Arizona, United States, located within the San Carlos Apache Indian Reservation. As of the 2010 census, its population was 1,962. The community has a medical clinic, a police substation, and a market. Bylas is an Apache settlement divided into two communities, …Bylas is an unincorporated community and census-designated place in Graham County, Arizona, United States, located within the San Carlos Apache Indian Reservation. As of the 2010 census, its population was 1,962. The community has a medical clinic, a police substation, and a market. Bylas is an Apache settlement divided into two communities, one of the White Mountain Apache, the other of San Carlos and Southern Tonto Apache. It is named for Bylas a chief of the Eastern White Mountain Apache band.