Joppa (/ˈdʒɒpə/ JOP-ə) is a former colonial town and current planning region of Harford County, Maryland, United States.

[3] Joppa's harbor began to silt in due to clearcutting and farming upriver and coupled with multiple outbreaks of diseases such as smallpox and malaria, the county seat was moved to the growing, deep water port of Baltimore in 1768.

The town of Joppa near the Western Shore of the Chesapeake Bay was designated as a "Port of Entry" by the colonial legislature, the Maryland General Assembly.

It traded internationally in agricultural products, primarily tobacco; the chief commodity crop and currency throughout much of its colonial era.

Joppa as it is known today is a planning region within Harford County and a federal zip code designation that includes modern day Joppatowne.