[21] Morris Plains was incorporated as a borough by an act of the New Jersey Legislature on March 15, 1926, from portions of Hanover Township, based on the results of a referendum held on April 15, 1926.

[22][23] The borough's name comes from Lewis Morris, colonial governor of New Jersey.

[24][25] Morris Plains serves as a bedroom community, with many residents traveling to work in New York City.

The Morristown Line of NJ Transit provides commuters with direct access to New York Penn Station and to Hoboken Terminal.

[1][2] Unincorporated communities, localities and place names located partially or completely within the township include Littleton.

[27][28][29] The climate in this area is characterized by hot, humid summers and generally mild to cool winters.

[30] The 2010 United States census counted 5,532 people, 2,131 households, and 1,485 families in the borough.

[35] As of the 2000 United States census[16] there were 5,236 people, 1,955 households, and 1,477 families residing in the borough.

[33][34] The borough has been a major base of operations for Pfizer, previously the headquarters for Warner-Lambert.

Pfizer has sponsored the Health and Medical Science Academy at Morristown High School and an annual 5k race around Morris Plains.

In 2012, a 63-acre (25 ha) property owned by Pfizer on the west side of Route 53 was acquired by M&M Realty Partners, which plans to redevelop the site for a mixed use development that would include 500 housing units and 100,000 square feet (9,300 m2) for retail use.

[6] The borough form of government used by Morris Plains 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.

[39][40] As of 2025[update], the mayor of Morris Plains is Democrat Jason C. Karr, whose term of office ends December 31, 2026.

[46][47][48] For the 119th United States Congress, New Jersey's 11th congressional district is represented by Mikie Sherrill (D, Montclair).

[50] 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).

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

[100] The one-story red brick station house, constructed in 1915 in Renaissance Revival style, was added to the National Register of Historic Places on June 22, 1984.