Salem is a city in Columbiana County, Ohio, United States. The population was 11,915 at the 2020 census. Salem was founded by Quakers in 1806 and played a key role in the abolitionist movement as a hub of the Underground Railroad. Initially an industrial town, Salem is primarily residential and a regional commercial hub. It is home to Allegheny Wesleyan College and Kent State University at Salem. It is the principal city of the Salem micropolitan area, which encompasses all of Columbiana County; a small portion of the city extends into southern Mahoning County.

Salem was founded by a New Jersey clockmaker, Zadok Street, and a Pennsylvanian potter, John Straughan, in 1806. The city was named after Salem, New Jersey, Street's native community. The name Salem itself is a biblical derivative of Jerusalem in the Middle East, which means "city of peace". The city's early settlers included the Religious Society of Friends, also known as Quakers, which the local school district's sports teams honor by referring to themselves collectively as the Salem Quakers. Salem was incorporated in 1830.

Salem was a center of abolitionist and suffragist activity in the 19th century. The Anti-Slavery Bugle, an abolitionist newspaper, was published in Salem beginning in 1845. A local group of the Progressive Friends, an association of Quakers who separated from the main body partly to be freer to work for such causes as abolitionism and women's rights, formed in Salem in 1849. The local school board at that time was composed entirely of abolitionists. Salem was the site of an annual conference, the Anti-Slavery Fair, whose purpose was to raise money for anti-slavery activities. The Daniel Howell Hise House and John Street House were stops on the Underground Railroad.

In April 1850, Salem hosted the first Women's Rights Convention in Ohio, the third such convention in the United States (the first two being the Seneca Falls Convention and Rochester Women's Rights Convention of 1848). The Salem Convention was the first of these conventions to be organized on a statewide basis. All the convention officers were women. Men were not allowed to vote, sit on the platform, or speak during the convention. The male spectators were supportive, however, and when the convention was over, they created an organization of their own and endorsed the actions of the women's convention.

Advantageously located between Cleveland and Pittsburgh, Salem thrived on an industrial-based economy in the 19th and 20th centuries. For several decades, Salem's largest employers included American Standard Brands, Eljer, Mullins Manufacturing, Deming Pump, and Salem China. Today, American Standard retains production in the city, as well as the Fresh Mark meat production facility and several tool-and-die manufacturers.

Salem is located about 18 miles (29 km) southwest of Youngstown, 28 miles (45 km) east of Canton, and 60 miles (97 km) southeast of Cleveland. According to the United States Census Bureau, the city has an area of 6.43 square miles (16.65 km²), all land. Salem is the largest incorporated place by area in Columbiana County.

The city is mostly surrounded by unincorporated Perry Township. Salem has annexed portions of Perry Township. Several acres of Salem Township and Green Township were annexed into the city limits in 2000 and 2001. Other actions to spur economic development undertaken around the same time annexed specific land: in 1999, 82.24 acres (332,800 m²) of Salem Township were granted police and fire protection, snow removal service, and other city services.

As of the census of 2010, there were 12,303 people, 5,272 households, and 3,118 families living in the city. The population density was 1,913.4 inhabitants per square mile (738.8/km²). There were 5,763 housing units at an average density of 896.3 per square mile (346.1/km²). The racial makeup of the city was 95.9% White, 0.7% African American, 0.2% Native American, 0.4% Asian, 1.6% from other races, and 1.2% from two or more races. Hispanic or Latino of any race were 2.5% of the population.