Silt'e is bordered on the south by Halaba, on the southwest by Hadiya, on the north by Gurage, and on the east by the Oromia Region.

Based on the 2007 Census conducted by the Central Statistical Agency of Ethiopia (CSA), Siltʼe Zone has a total population of 750,398, of whom 364,108 are men and 386,290 women; 78,525 or 6.28% are urban inhabitants.

The largest ethnic group reported in Silt'e was the Silt'e people (97.35%); all other ethnic groups made up 2.65% of the population.

Silt'e is spoken as a first language by 96.95% of the population, and 1.54% speak Amharic; the remaining 1.51% speak all other primary languages reported.

The majority of the inhabitants were reported as Muslim, with 97.6% of the population reporting that belief, while 2.03% practiced Ethiopian Orthodox Christianity.