Nigeria

The length of Nigeria’s borders is 4047 kilometers.

An excerpt from the article 19 facts about Nigeria

It is bordered by four countries: Niger to the north, Chad to the northeast, Cameroon to the east, and Benin to the west. In the south it borders the Atlantic Ocean (Gulf of Guinea) - the coastline is 853 kilometers long. In the northeastern corner of the country, on the shared water border with Niger, Chad, and Cameroon, is the drainless Lake Chad.