Maryland County is a county in the southeastern portion of Liberia. One of 15 counties that comprise the first-level of administrative division in the nation, it has four districts. Harper serves as the capital with the area of the county measuring 2,297 square kilometres (887 sq mi). As of the 2008 Census, it had a population of 135,912, making it the seventh most populous county in Liberia.

Named after the State of Maryland in the United States, it joined Liberia in 1857. The most populous city in the county is Pleebo with 22,963 residents. The county is bordered by Grand Kru County to the west and River Gee County to the north. The eastern part of Maryland borders the nation of Côte d'Ivoire, separated by the Cavalla River.

Maryland County Superintendent is Hon. D. I. Sie-Teba Neufville