NEW YORK — Southern U.S. ports are experiencing a record foreign trade boom thanks in part to an expanded Panama Canal that permits Asian cargo ships to reach them more easily.

Georgia Ports Authority and the Port of Virginia, which include the nation's fourth and fifth largest ranked by volume, respectively, each moved the most cargo they have ever handled in May. The two ports posted more than 10 percent year-over-year volume growth for the month.

They aren't alone. South Carolina State Ports Authority, which includes the Port of Charleston, had its best ever month in March, April and May and overall volume from last July through May is up 9.4 percent compared to a year earlier.

"We've candidly been surprised by the strength of the volume growth for the first part of this calendar year. January through April has been very strong," said Jim Newsome, the SPA's president and chief executive officer.

The uptick in foreign trade throughout the region comes thanks in part to the June 26 completion of the widening of the Panama Canal, which allowed the larger vessels that shipping lines favor to travel between Asia and the eastern seaboard through the passage.

Previously, ports on the West Coast, which include the nation's largest by volume, typically handled such ships.

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The expansion also coincided with a population boom that has made the South home to 10 of the 15 fastest-growing cities, according to the Census Bureau, meaning there is a growing market for goods being imported.

At the same time, manufacturing growth throughout the south means shipping lines also can pick up American-made exports to transport abroad.

A more even trade balance compared to West Coast ports, which rely more heavily on imports, is an attractive draw for shipping firms considering southeastern ports, according to Moses Kopmar, an analyst with Moody's Investors Service.

"The population growth is among the strongest in terms of the regions of the U.S., it's where the majority of recent and new manufacturing activity is located, and you have relatively good import, export trade balances," Kopmar said.