Changnyeong-gun is a county located at the northern end of Gyeongsangnam-do (South Gyeongsang) Province and it is bordered by Dalseong County in Daegu and Goryeong County of Gyeongsangbuk-do (North Gyeongsang) Province to the north and, Cheongdo County in Gyeongsangbuk-do Province and Miryang in Gyeongsangnam-do Province to the east.
The county is also bordered by Hapcheon County, Uiryeong County, Haman County and Changwon to the southwest.