Mansfield Township became part of the newly formed Warren County on November 20, 1824.

In 1835, it was the site of America's first successful use of the hot blast in which preheated air was blown into the furnace, cutting production time.

Oxford Furnace is listed on the State and the National Register of Historic Places.

[24] Other unincorporated communities, localities and place names located partially or completely within the township include Pequest.

[28][29] Being in the Northeast U.S., Oxford experiences all four seasons with hot humid summers and cold, snowy winters.

The township's economic data (as is all of Warren County) is calculated by the US Census Bureau as part of the Allentown-Bethlehem-Easton, PA-NJ Metropolitan Statistical Area.

The 2010 United States census counted 2,514 people, 950 households, and 675 families in the township.

[41] As of the 2000 United States census,[12] there were 2,307 people, 886 households, and 618 families residing in the township.

[3][44][45][46][47][48] In August 2021, the committee selected Linda Koufodontes to fill the vacant seat expiring in December 2023 that had been held by Robert Nyland until he resigned from office.

[46][49][50] After committee member Keith Gibbons resigned in July 2014 in the wake of harassment claims,[51] Mayor Jade White and committee member Jim Williams resigned in August 2014 after realizing that Williams should have been up for election the previous November following his appointment to office.

[52] In September 2014, Governor Chris Christie appointed Democrat Bill Bray and Republicans Marck Pasquini and Bill Ryan to fill the three vacant seats on an interim basis until the November 2014 general election, with the committee selecting Pasquini as mayor and Ryan as deputy mayor.

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

[58] 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).

[63][64] Constitutional officers of Warren County are: Clerk Holly Mackey (R, Alpha; 2027),[65][66] Sheriff James McDonald Sr. (R, Phillipsburg; 2025)[67][68] and Surrogate Michael J. Doherty (R, Washington; 2025).

[72] Among the township's 2010 Census population, 58.2% (vs. 62.3% in Warren County) were registered to vote, including 76.6% of those ages 18 and over (vs. 81.5% countywide).

[84][85] Schools in the district (with 2018–19 enrollment data from the National Center for Education Statistics[86]) are Warren Hills Regional Middle School[87] with 542 students in grades 7 and 8 (located in Washington Borough) and Warren Hills Regional High School[88] with 1,205 students in grades 9–12 (located in Washington Township).

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