Montserrado County is a county in the northwestern portion of Liberia. One of 15 counties that comprise the first-level of administrative division in the nation, it has four districts. Bensonville serves as the capital with the area of the county measuring 1,909 square kilometres (737 sq mi), the smallest in the country. As of the 2008 Census, it had a population of 1,144,806, making it the most populous county in Liberia.

Created in 1847 at the foundation of the country, the county is the oldest in Liberia. The most populous city in the county is Liberia’s capital, Monrovia with 1,010,970 residents. The county is bordered by Bomi County to the west, Bong County to the north, and Margibi County to the east. The southern part of Montserrado lies on the Atlantic Coast.

Montserrado County Superintendent is Hon. Nyenekon Beauty Snoh-Barcon.