Cambridge is the county seat of Guernsey County, Ohio. Residents named the town after Cambridge, Maryland. In 1806, residents established the town, which was located along Zane's Trace. Eventually, the National Road also passed through the community, making Cambridge a center of trade.
Cambridge grew relatively quickly. Nearly one thousand people resided in the community by 1840. The town consisted of four churches, nine stores, one flour and two fulling mills, and one newspaper office. By the American Civil War, two railroads intersected in the town, causing further growth. By 1880, 2,833 residents lived in Cambridge, and the town now included five newspaper offices, seven churches, and three banks. Numerous manufacturing businesses operated in the town. In 1886, the largest employer was the Cambridge Chair Factory, with seventy-five employees. Other businesses manufactured doors, iron roofs, and buggies, among other items. During the late 1880s and the early 1890s, residents discovered deposits of natural gas and oil. These two items led to the creation of a glass-making industry. While the city's glass production declined during the twentieth century, a tourist industry, consisting largely of glass collectors, arose in its place.
During the twentieth century, Cambridge continued to grow in population. In 2000, the community had 11,520 people. This amounted to over twenty-five percent of Guernsey County's total population. Many residents currently find employment in travel-related businesses, with both Interstate 70 and Interstate 77 passing through Cambridge.