Providence County was constituted on June 22, 1703, as the County of Providence Plantations. It consisted of five towns, namely Providence, Warwick, Westerly, Kingstown, and Greenwich and encompassed territory in present-day Kent and Washington counties.
The town of Cumberland was acquired from Massachusetts and added to Providence County in 1746–47, and the towns of East Providence and Pawtucket were made part of Providence County when the final border with Massachusetts was settled in 1862.