[1][2] Brainards (with a 2010 population of 202[20]) Harmony CDP (441[21]) and Hutchinson (135[22]) are unincorporated communities and census-designated places (CDPs) located within the township.

[23][24][25] Other unincorporated communities, localities and place names located partially or completely within the township include Allens Mills, Harmony Station, Lower Harmony, Martins Creek Station, Montana and Roxburg.

[27][28] The township's economic data, like all of Warren County, is calculated by the U.S. Census Bureau as part of the Allentown-Bethlehem-Easton, PA-NJ Metropolitan Statistical Area.

The 2010 United States census counted 2,667 people, 1,017 households, and 760 families in the township.

[40] As of the 2000 United States census[12] there were 2,729 people, 1,010 households, and 786 families residing in the township.

17.8% of all households were made up of individuals, and 8.5% had someone living alone who was 65 years of age or older.

[5][42] At an annual reorganization meeting, the Township Committee selects one of its members to serve as Mayor.

[48][49][50] Prior to the 2010 Census, Harmony Township had been part of the 5th Congressional District, a change made by the New Jersey Redistricting Commission that took effect in January 2013, based on the results of the November 2012 general elections.

[51] For the 119th United States Congress, New Jersey's 7th congressional district is represented by Thomas Kean Jr. (R, Westfield).

[53] For the 2024-2025 session, the 23rd legislative district of the New Jersey Legislature is represented in the State Senate by Doug Steinhardt (R, Lopatcong Township) and in the General Assembly by John DiMaio (R, Hackettstown) and Erik Peterson (R, Franklin Township).

[58][59] Constitutional officers of Warren County are: Clerk Holly Mackey (R, Alpha; 2027),[60][61] Sheriff James McDonald Sr. (R, Phillipsburg; 2025)[62][63] and Surrogate Michael J. Doherty (R, Washington; 2025).

[67] Among the township's 2010 Census population, 67.6% (vs. 62.3% in Warren County) were registered to vote, including 85.5% of those ages 18 and over (vs. 81.5% countywide).

The closest limited access road is Interstate 78 which is in neighboring Greenwich and Franklin.

People who were born in, residents of, or otherwise closely associated with Harmony Township include: