‍The Marysville-Union County Port Authority is a statutory agent of Union County created by the Union County Board of Commissioners. Port Authorities were originally created to operate actual maritime ports, lake and river ports, as well as airports. Over time, the legal powers of ports have proven useful in serving the public interest for economic development as well as navigation.

While the Union County-Marysville Port Authority does not operate a traditional port, under the Ohio Revised Code, port authorities are given certain powers in the areas of real estate development, financing and management of foreign trade zones. Unlike a city or county, port authorities can buy land and construct a building that could be leased or sold to a business of its choosing at a privately negotiated price. They can also issue tax-exempt (and therefore, lower interest bonds) on behalf of a private entity for the construction of a new plant or equipment.

The Marysville-Union County Port Authority is a proud member of the Ohio Council of Port Authorities.