The Rock Flat Creek (technically a river) rises below One Tree Hill, on the lower slopes of the Snowy Mountains, part of the Great Dividing Range. The creek flows generally north by west before reaching its confluence with the Cooma Creek just upstream from that creek's confluence to form the Numeralla River (itself a tributary of the Murrumbidgee River), north of the town of Cooma. The creek descends over its course.