Final answer:
The city of Cologne, located in Germany, is a prominent port on the Rhine River, which is integral to Central European trade and Germany's economy.
Step-by-step explanation:
The country that has Cologne, a port on the Rhine, is Germany. Cologne is situated in western Germany and is one of the country's major cities. Notably, the Rhine River plays a significant role in the transportation of goods and the economic activity in Central Europe.
Barges navigate along the Rhine to transport goods, benefiting from the river as a vital pathway for industrial activity. The Rhine connects with important industrial regions including the historical Ruhr industrial complex and reaches all the way to the North Sea through the Rhine-Main-Danube Canal.
Furthermore, the importance of the Rhine extends to its connection to Europe's busiest port of Rotterdam in the Netherlands. In the broader context, the Rhine River aids Germany in sustaining its status as Europe's largest economy and having the largest GDP overall as a country.