Pulitzer Prize-winning Washington Post photojournalist Michael S. Williamson enjoys a good road trip. Either for work or pleasure, he has often crisscrossed the country, repeatedly tackled the transcontinental Lincoln Highway and driven Route 66 at least a dozen times. But until he started photographing infrastructure along the Mississippi River, Williamson had never undertaken any extensive north-south journeys. “I was up for the challenge of following a waterway versus a roadway,” he said.

While the river is only about 2,300 miles in length, Williamson chased good light, competed with snowmobiles, and zigzagged across some of the 170 bridges to photograph the river’s main sights and towns. “The river is the state line in most places, so if you drive the river north to south to see the western side you must start all over and travel south to north to see the states on the eastern side,” he explained.

The Mississippi River watershed — the third-largest in the world — drains an area of about 1.2 million square miles, including all or part of 31 states and two Canadian provinces, and about 40 percent of the continental United States. The river itself travels through 10 states, and it takes about 90 days for water that leaves Lake Itasca, the river’s source, to reach the Gulf of Mexico.

From ice fishing up north to jet-skiing down south, communities along the river differed in culture as much as climate, Williamson found. But, he says, they were all shaped by their proximity to the river.

“I made lots of photos of old bridges and tall levees that protected the towns. The river wasn’t necessarily in every frame,” he said. “But, you knew it was close by.”

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