Salem County is the westernmost county in the U.S. state of New Jersey. Its western boundary is formed by the Delaware River, and it has the eastern terminus of the Delaware Memorial Bridge, which connects the county with New Castle, Delaware. Its county seat is Salem. The county is part of the South Jersey region of the state.

The county lies within the Philadelphia metropolitan area, also known as the Delaware Valley area. As of the 2020 census, the county retained its position as the state's least-populous county, with a population of 64,837, a decrease of 1,246 (−1.9%) from the 2010 census count of 66,083. The most populous place in Salem County is Pennsville Township with 12,684 residents as of the 2020 Census. Lower Alloways Creek Township covers 72.46 square miles (187.7 km), the largest total area of any municipality.

Salem County, along with adjacent Gloucester County, also in South Jersey, have become an East Coast epicenter for logistics and warehouse construction.

The county derives its name from the Hebrew word shalom, which means "peace", chosen by early Quaker settlers to mark the serenity of the area.

European settlement began with English colonists in the seventeenth century, who were settling both sides of the Delaware River. They established a colonial court in the area in 1681, but Salem County was first formally organized within West Jersey on May 17, 1694, from the Salem Tenth. Pittsgrove Township was transferred to Cumberland County in April 1867, but was restored to Salem County in February 1868. The area was initially settled by Quakers.

The Old Salem County Courthouse, located on the same block as the Salem County Courthouse, serves as the court for Salem City in the 21st century. It is the oldest active courthouse in New Jersey and is the second oldest courthouse in continuous use in the United States, the oldest being King William County Courthouse in Virginia. The courthouse was built in 1735 during the reign of King George II using locally manufactured bricks. The building was enlarged in 1817 and additionally enlarged and remodeled in 1908. Its distinctive bell tower is essentially unchanged and the original bell sits in the courtroom.

Judge William Hancock of the King's Court presided at the courthouse. He was later killed by the British in the American Revolutionary War during the massacre at Hancock House committed by the British against local militia during the Salem Raid in 1778. Afterward the courthouse was the site of the "treason trials", wherein suspected Loyalists were put on trial for having allegedly aided the British during the Salem Raid. Four men were convicted and sentenced to death for treason; however, they were pardoned by Governor William Livingston and exiled from New Jersey. The courthouse is also the site of the legend of Colonel Robert Gibbon Johnson's proving the edibility of the tomato. Before 1820, Americans often assumed tomatoes were poisonous. In 1820, Colonel Johnson, according to legend, stood upon the courthouse steps and ate tomatoes in front of a large crowd assembled to watch him do so.

Salem County is notable for its distinctive Quaker-inspired architecture and masonry styles of the 18th century. It had a rural and agricultural economy. In the early 20th century, its towns received numerous immigrants from eastern and southern Europe, who markedly added to the population. In the period following World War II, the county's population increased due to suburban development. To accommodate increasing traffic, the Delaware Memorial Bridge was built from Salem County to New Castle, Delaware.

According to the U.S. Census Bureau, as of the 2020 Census, the county had a total area of 372.55 square miles (964.9 km), of which 331.86 square miles (859.5 km) was land (89.1%) and 40.69 square miles (105.4 km) was water (10.9%). The county is bordered on the west by the Delaware River, and drained by Salem River, Alloway, and other creeks.

The terrain is almost uniformly flat coastal plain, with minimal relief. The highest elevation in the county has never been determined with any specificity, but is likely one of seven low rises in Upper Pittsgrove Township that reach approximately 160 feet (49 m) in elevation. Sea level is the lowest point.

The county has a humid subtropical climate (Cfa) and monthly temperatures in Salem city average from 33.2 °F (0.7 °C) in January to 77.2 °F (25.1 °C) in July, while in Elmer they average from 33.1 °F (0.6 °C) in January to 76.8 °F (24.9 °C) in July.

Salem, New Jersey
Climate chart (explanation)
J F M A M J J A S O N D     3     40 25     2.8     44 27     3.9     52 34     3.5     64 43     4     73 53     3.9     82 63     4.6     86 68     3.3     84 66     4.3     77 58     3.4     66 46     3.1     56 37     3.5     45 29 █ Average max. and min. temperatures in °F █ Precipitation totals in inches Source: The Weather Channel
Metric conversion J F M A M J J A S O N D     76     4 −4     71     7 −3     100     11 1     89     18 6     100     23 12     99     28 17     116     30 20     83     29 19     110     25 14     87     19 8     79     13 3     88     7 −2 █ Average max. and min. temperatures in °C █ Precipitation totals in mm

In recent years, average temperatures in the county seat of Salem have ranged from a low of 25 °F (−4 °C) in January to a high of 86 °F (30 °C) in July, although a record low of −14 °F (−26 °C) was recorded in January 1985 and a record high of 107 °F (42 °C) was recorded in August 1918. Average monthly precipitation ranged from 2.78 inches (71 mm) in February to 4.57 inches (116 mm) in July.

Historical population

Census	Pop.	Note	%±
1790	10,437		—
1800	11,371		8.9%
1810	12,761		12.2%
1820	14,022		9.9%
1830	14,155		0.9%
1840	16,024		13.2%
1850	19,467		21.5%
1860	22,458		15.4%
1870	23,940		6.6%
1880	24,579		2.7%
1890	25,151		2.3%
1900	25,530		1.5%
1910	26,999		5.8%
1920	36,572		35.5%
1930	36,834		0.7%
1940	42,274		14.8%
1950	49,508		17.1%
1960	58,711		18.6%
1970	60,346		2.8%
1980	64,676		7.2%
1990	65,294		1.0%
2000	64,285		−1.5%
2010	66,083		2.8%
2020	64,837		−1.9%
2023 (est.)	65,338		0.8%
Historical sources: 1790-1990 1970-2010 2010 2020

As of the 2020 U.S. census, the county's had 64,837 people, 24,404 households, and 16,880 families. The population density was 195.35 inhabitants per square mile (75.4/km). There were 27,763 housing units at an average density of 83.64 per square mile (32.3/km). The racial makeup was 79.0% White, 13.1% African American, 0.3% Native American, 1.1% Asian, and 3.7% from two or more races. Hispanic or Latino of any race were 9.8% of the population.

Of the 24,404 households, of which 21.0% had children under the age of 18 living with them, 48.6% were married couples living together, 14.9% had a female householder with no husband present, 5.6% had a male householder with no wife present and 30.8% were non-families, and 12.4% had someone living alone who was 65 years of age or older. The average household size was 2.50 and the average family size was 3.03.

About 21.0% of the population was under age 18, 8.0% was from age 18 to 24, 35.2% was from age 15 to 44, and 19.8% was age 65 or older. The median age was 43.1 years. The gender makeup was 47.9% male and 52.1% female. For every 100 females, there were 92.1 males.

The median household income was $68,531, and the median family income was $81,122. About 12.4% of the population were below the poverty line, including 20.2% of those under age 18 and 4.7% of those age 65 or over.

The 2010 United States census counted 66,083 people, 25,290 households, and 17,551 families in the county. The population density was 199.1 inhabitants per square mile (76.9/km). There were 27,417 housing units at an average density of 82.6 per square mile (31.9/km). The racial makeup was 79.83% (52,757) White, 14.09% (9,309) Black or African American, 0.36% (240) Native American, 0.84% (557) Asian, 0.02% (10) Pacific Islander, 2.64% (1,745) from other races, and 2.22% (1,465) from two or more races. Hispanic or Latino of any race were 6.82% (4,507) of the population.

Of the 25,290 households, 29% had children under the age of 18; 49.9% were married couples living together; 14.4% had a female householder with no husband present and 30.6% were non-families. Of all households, 25.4% were made up of individuals and 10.9% had someone living alone who was 65 years of age or older. The average household size was 2.56 and the average family size was 3.07.

23.5% of the population were under the age of 18, 8.2% from 18 to 24, 23.9% from 25 to 44, 29.4% from 45 to 64, and 15% who were 65 years of age or older. The median age was 40.8 years. For every 100 females, the population had 94.9 males. For every 100 females ages 18 and older there were 91.6 males.

Salem County is governed by a five-member Board of Commissioners who are elected at-large to serve three-year terms of office on a staggered basis, with either one or two seats coming up for election each year. At an annual reorganization meeting held at the beginning of January, the board selects a director and a deputy director from among its members. The appointed position professional county administrator was abolished by a unanimous vote of the commissioners in January 2014. In 2016, commissioners were paid $25,410 and the director was paid an annual salary of $26,410.

In the 2016 general election, Salem County voters approved a binding referendum to cut the number of Commissioner from seven to five as well as a non-binding referendum to cut Commissioner salaries by 20%; both initiatives, which had been placed on the ballot as the result of grassroots campaigns opposed to a proposed outsourcing deal, passed by a 3–1 margin. In the wake of the referendum results, Director Julie Acton resigned in December 2016 and was replaced by Scott Griscom. In April 2017, the New Jersey Supreme Court ruled that the reduction in seats will be accomplished through attrition, with the seats expiring at the end of 2017 (held by Commissioners Cross, Painter, and Vanderslice) being eliminated; in the November 2017 general election there will be one new three-year seat up for a vote as well as a two-year unexpired term, so that on January 1, 2018, there will be a five-member board. Republicans have fully controlled the board since 2022.

As of 2024, Salem County's Commissioners (with terms for director and deputy director ending every December 31) are:

Commissioner	Party, Residence, Term
Director Ben H. Laury	R, Elmer, 2024
Deputy Director Mickey Ostrum Jr.	R, Pilesgrove Township, 2024
Ed Ramsay	R, Pittsgrove Township, 2026
Cordy Taylor	R, Oldmans Township, 2025
Daniel Timmerman	R, Elmer, 2025

Pursuant to Article VII Section II of the New Jersey State Constitution, each county in New Jersey is required to have three elected administrative officials known as "constitutional officers." These officers are the County Clerk and County Surrogate (both elected for five-year terms of office) and the County Sheriff (elected for a three-year term). Salem County's constitutional officers, elected on a countywide basis are:

Title	Representative
County Clerk	Dale A. Cross (R, Pennsville Township, 2024)
Sheriff	Charles M. Miller (R, Salem, 2024)
Surrogate	Nicki A. Burke (R, Woodstown, 2025).

The Salem County Prosecutor is Kristin J. Telsey, who was nominated to fill the position in September 2022. Salem County is a part of Vicinage 15 of the New Jersey Superior Court (along with Cumberland County and Gloucester County), seated in Woodbury in Gloucester County; the Assignment Judge for the vicinage is Benjamin C. Telsey. The Salem County Courthouse is in Salem. No Democrat has one county-wide office since 2020.

Salem County falls entirely within the 2nd congressional district For the 118th United States Congress, New Jersey's 2nd congressional district is represented by Jeff Van Drew (R, Dennis Township).

All of Salem County is located in the 3rd legislative district.

District	Senator	Assembly	Notes
3rd	John Burzichelli (D)	Heather Simmons (D) Dave Bailey (D)	The remainder of this district includes portions of Cumberland and Gloucester counties.

As of January 2023, there were a total of 48,956 registered voters in Salem County, of whom 14,768 (30.2%) were registered as Democrats, 14,839 (30.3%) were registered as Republicans and 18,525 (37.8%) were registered as unaffiliated. There were 824 voters (1.7%) registered to other parties. Among the county's 2010 Census population, 64.6% were registered to vote, including 84.4% of those ages 18 and over.

Salem County generally and historically leaned towards the Republican Party, but not as much so as the Northwest or Shore regions of the state. In the 2008 presidential election, Democrat Barack Obama carried the county by a 4% margin over Republican John McCain, with Obama receiving 57.27% statewide. Obama received 16,044 votes here (50.4%), ahead of McCain with 14,816 votes (46.6%) and other candidates with 503 votes (1.6%), among the 31,812 ballots cast by the county's 44,324 registered voters, for a turnout of 71.8%. In the 2012 presidential election, Democrat Barack Obama narrowly finished ahead of Republican Mitt Romney; the state voted for Obama. Since 2012, the county has swung more toward Republicans, following the trend of most rural counties in the United States. Republican Donald Trump won 54.9% of the vote in 2016, the highest vote share for a Republican since George H. W. Bush in 1988. Trump improved to 55.3% of the vote in winning the county again in 2020.

United States presidential election results for Salem County, New Jersey

Year	Republican		Democratic		Third party(ies)
	No.	%	No.	%	No.	%
2020	18,827	55.31%	14,479	42.53%	736	2.16%
2016	16,381	54.87%	11,904	39.88%	1,568	5.25%
2012	14,334	48.39%	14,719	49.69%	570	1.92%
2008	14,816	46.99%	16,044	50.88%	672	2.13%
2004	15,721	52.79%	13,749	46.17%	311	1.04%
2000	12,257	45.44%	13,718	50.86%	997	3.70%
1996	9,294	35.76%	12,044	46.34%	4,654	17.91%
1992	10,363	37.10%	10,062	36.02%	7,510	26.88%
1988	15,240	59.52%	9,956	38.88%	410	1.60%
1984	17,368	65.66%	8,935	33.78%	149	0.56%
1980	13,000	51.03%	10,209	40.08%	2,265	8.89%
1976	11,639	46.60%	12,826	51.35%	512	2.05%
1972	16,371	64.84%	8,609	34.10%	269	1.07%
1968	11,407	43.45%	11,172	42.56%	3,672	13.99%
1964	8,682	32.71%	17,846	67.23%	17	0.06%
1960	14,192	53.34%	12,394	46.58%	21	0.08%
1956	14,091	60.16%	9,276	39.60%	56	0.24%
1952	12,026	51.30%	11,362	48.47%	54	0.23%
1948	8,961	48.65%	9,278	50.37%	179	0.97%
1944	7,942	43.38%	10,345	56.50%	23	0.13%
1940	8,132	39.80%	12,244	59.92%	57	0.28%
1936	7,671	39.54%	11,614	59.86%	117	0.60%
1932	9,870	56.64%	7,357	42.22%	198	1.14%
1928	12,323	80.23%	3,001	19.54%	36	0.23%
1924	8,027	68.86%	3,206	27.50%	424	3.64%
1920	7,638	66.50%	3,483	30.33%	364	3.17%
1916	4,080	53.77%	3,353	44.19%	155	2.04%
1912	1,803	29.65%	2,745	45.14%	1,533	25.21%
1908	3,713	52.91%	3,174	45.23%	131	1.87%
1904	3,694	54.69%	2,775	41.08%	286	4.23%
1900	3,395	50.59%	2,982	44.43%	334	4.98%
1896	3,717	54.37%	2,802	40.99%	317	4.64%

In the 2009 gubernatorial election, Republican Chris Christie received 9,599 votes here (46.1%), ahead of Democrat Jon Corzine with 8,323 votes (39.9%), Independent Chris Daggett with 2,011 votes (9.7%) and other candidates with 411 votes (2.0%), among the 20,838 ballots cast by the county's 44,037 registered voters, yielding a 47.3% turnout. In the 2013 gubernatorial election, Republican Chris Christie received 12,748 votes in the county (66.6%), ahead of Democrat Barbara Buono with 5,889 votes (30.7%). In the 2017 gubernatorial election, Republican Kim Guadagno received 8,629 (50.1%) of the vote, and Democrat Phil Murphy received 7,814 (45.3%) of the vote. In the 2021 gubernatorial election, Republican Jack Ciattarelli received 64.1% of the vote (12,620 ballots cast) to Democrat Phil Murphy's 35.0% (6,893 votes).

The Bureau of Economic Analysis calculated that the county's gross domestic product was $5.2 billion in 2021, which was ranked 18th in the state and was a 3.9% increase from the prior year.

School districts include:

K-12

• Penns Grove-Carneys Point Regional School District
• Pennsville School District
• Pittsgrove Township School District
• Salem City School District
• Salem County Special Services School District
• Woodstown-Pilesgrove Regional School District – Regional

Secondary

• Salem County Vocational Technical Schools

Elementary

Elmer School District became a non-operating school district in 2010, and disestablished completely in 2017.

As of 2010, the county had a total of 879.53 miles (1,415.47 km) of roadways, of which 429.36 miles (690.99 km) were maintained by the local municipality, 355.17 miles (571.59 km) by Salem County and 85.94 miles (138.31 km) by the New Jersey Department of Transportation, 8.11 miles (13.05 km) by the New Jersey Turnpike Authority and 0.95 miles (1.53 km) by the Delaware River and Bay Authority.

Salem is served by many roads. Major county routes include CR 540, CR 551, CR 553 (only in Pittsgrove) and CR 581. State highways include Route 45, Route 48 (only in Carneys Point), Route 49, Route 56 (only in Pittsgrove), Route 77 and Route 140 (only in Carneys Point). The U.S. routes are U.S. Route 40 and the southern end of U.S. Route 130.

Limited access roads include Interstate 295 and the New Jersey Turnpike. Both highways pass through the northern part of the county. Only one turnpike interchange is located in Salem: Exit 1 in Carneys Point (which is also where the turnpike ends). There are a pair of service areas on the Turnpike, both located between exits 1 and 2 in Oldmans Township: The John Fenwick Service Area on the northbound side and the Clara Barton Service Area in the southbound direction. The Route 55 freeway passes through the northeastern part of the county briefly but has no interchanges within the county.

The Delaware Memorial Bridge (which is signed as I-295/US 40) is a set of twin suspension bridges crossing the Delaware River. Connecting New Castle, Delaware and Pennsville Township, the original span was opened in 1951 and the second span in 1968.

NJ Transit operates three routes through Salem County: the 401, which stops in Salem, Woodstown, Swedesboro, and Woodbury en route to and from Philadelphia; the 402, which stops in Penns Grove and has two stops in Salem en route to and from Philadelphia; and the 468, which has local stops throughout Salem County.