[20] Riverdale was incorporated as a borough by an act of the New Jersey Legislature on March 12, 1923, from portions of Pequannock Township, subject to the results of a referendum passed on April 17, 1923.

[1][2] The borough is bordered by the municipalities of Butler and Kinnelon to the west and by Pequannock Township to the south, all in Morris County; and by Bloomingdale to the north and Pompton Lakes to the east in Passaic County.

[23][24][25] The 2010 United States census counted 3,559 people, 1,547 households, and 917 families in the borough.

Of all households, 33.2% were made up of individuals and 10.4% had someone living alone who was 65 years of age or older.

[31] As of the 2000 United States census[15] there were 2,498 people, 919 households, and 671 families residing in the borough.

21.1% of all households were made up of individuals, and 7.4% had someone living alone who was 65 years of age or older.

The mayor is elected directly by the voters to a four-year term of office.

[6] The borough form of government used by Riverdale is a "weak mayor / strong council" government in which council members act as the legislative body with the mayor presiding at meetings and voting only in the event of a tie.

The mayor can veto ordinances subject to an override by a two-thirds majority vote of the council.

[5][34][35] As of 2023[update], the mayor of Riverdale is Republican Paul M. Carelli, whose term of office ends December 31, 2023.

[44] For the 119th United States Congress, New Jersey's 11th congressional district is represented by Mikie Sherrill (D, Montclair).

[46] For the 2024-2025 session, the 26th legislative district of the New Jersey Legislature is represented in the State Senate by Joseph Pennacchio (R, Rockaway Township) and in the General Assembly by Brian Bergen (R, Denville Township) and Jay Webber (R, Morris Plains).

[48] Actual day-to-day operation of departments is supervised by County Administrator Deena Leary.

[95][96][97] In September 2012, as part of budget cuts, NJ Transit suspended service to Newark on the 75 line.