Monmouth County is a county located in the central portion of the U.S. state of New Jersey. It is bordered to its west by Mercer and Middlesex Counties, to its south by Ocean County, to its east by the Atlantic Ocean, and to its north by the Raritan Bay. Monmouth County's geographic area comprises 30% water. The county is part of the Jersey Shore region of the state. It has also been categorized under the Central Jersey region, though it was not among the four counties explicitly listed as included in Central Jersey as part of legislation signed by Governor Phil Murphy into law in 2023.