[4] Providence County contains the city of Providence, the state capital of Rhode Island and the county's (and state's) most populous city, with an estimated 190,934 residents in 2020.

As of 2010, the center of population in Rhode Island is located in Providence County, in the city of Cranston.

It consisted of five towns, namely Providence, Warwick, Westerly, Kingstown, and Greenwich and encompassed territory in present-day Kent and Washington counties.

The county is drained by the Blackstone River, which runs partly along the east border, the Woonasquatucket River in the central part of the county, joining with the smaller Moshassuck River in downtown Providence, and the Pawtuxet, which forms a portion of the southeastern boundary of the county.

[7] The Pawtuxet is dammed in the western part of the county to form the Scituate Reservoir, which supplies drinking water for Providence and surrounding communities.

The highest natural point in the county and the state of Rhode Island is Jerimoth Hill at 812 feet (247 m).

72.7% spoke English, 13.4% Spanish, 4.9% Portuguese, 2.5% French and 1.6% Italian as their first language.

29.80% of all households were made up of individuals, and 11.90% had someone living alone who was 65 years of age or older.

[13] As of the 2010 United States census, there were 626,667 people, 241,717 households, and 149,691 families living in the county.

Richard Nixon is the last Republican presidential candidate to have won the county, doing so in his 1972 landslide.