Bomi is one of 15 counties that comprise the first-level of administrative division in the nation. Tubmanburg serves as the county's capital. The County has four administrive districts.

Bomi is bordered on the northwest by Grand Cape Mount County, on the northeast by Gbarpolu and Bong Counties, on the southeast by Montserrado County and on the southwest by the Atlantic Ocean. As of the 2008 Liberian census, Bomi had a population of 84,119, making it the nation's eleventh most populous county.