Sinoe has 17 districts, Greenville is the county's capital. Sinoe has the third-largest area of all Liberia's counties; it has the second least-dense population after Gbarpolu County. The County was originally a colony in the name Mississippi-in-Africa, under auspices of a chapter of the American Colonization Society as it was created with slaves from Mississippi to Liberia.

There are seventeen districts in the county and it has lower tropical forests which has mid size hills composed of various valleys and water courses. Sapo National Park, a National protected area, Sankwehn Proposed Reserve, occupying an area of 198,540 acres,