During the Gettysburg campaign of the American Civil War in the summer of 1863, Confederate troops marched through the Cumberland Valley, briefly occupying much of the county.

In the 20th century, the suburbs of Harrisburg, the state capital, expanded extensively into eastern Cumberland County.

A large portion of Cumberland is drained by the Conodoguinet Creek, which winds its way west-to-east across the county into the Susquehanna.

Almost all of Cumberland has a hot-summer humid continental climate (Dfa) and its hardiness zone is 7a, except in small higher areas near the NW and SW boundaries, where it is 6b.

[6] The latest temperature averages show some low-lying eastern areas of the county to have a humid subtropical climate (Cfa.)

The United States Office of Management and Budget[16] has designated Cumberland County as part of the Harrisburg-Carlisle, PA Metropolitan Statistical Area (MSA).

The most recent Democrat to win the county in a presidential election was Lyndon B. Johnson in 1964 who won in a landslide statewide & nationally.

In 2024, Kamala Harris won 44.45% of the vote in the county, the highest percentage since 1964, despite losing Pennsylvania and the 2024 presidential election.

All row offices and all legislative seats serving Cumberland are held by Republicans except for one State Representative.

School districts include:[24] As reported by the National Center for Educational Statistics[27] Under Pennsylvania law, there are four types of incorporated municipalities: cities, boroughs, townships, and, in at most two cases, towns.

The following boroughs and townships are located in Cumberland County: Census-designated places are geographical areas designated by the U.S. Census Bureau for the purposes of compiling demographic data.

The Capital City Mall in Lower Allen Township serves the West Shore, the Carlisle area, and surrounding communities.