Ever wondered who makes up the local jail population? 857-Inmates are currently being held in the Rutherford County Adult Detention Center, according to Sheriff Robert Arnold. Of those jailed, 67% are white, 31% are black and 2-percent are categorized as other. As far as the age of the average inmate goes, the average male inmate is 32-years old and the average female is 33. The average length of stay for an inmate, male or female is 127-days. 387-Inmates face misdemeanor offenses and 470-face felonies. 252-Male inmates are awaiting transfer to a state penitentiary and 33-females are in line for a state jail as of March 21st.