SHARPSBURG, Md. (CBSDC/AP) — The National Park Service is encouraging people to leave the Chesapeake and Ohio Canal National Historical Park.

It’s part of a program urging hikers and bikers to visit nearby Potomac River towns.

On Tuesday, rangers and volunteers erected signs inviting canal towpath users to make side trips to Sharpsburg, Md., and Shepherdstown, W.Va.

The seventh and final sign will be installed later this year near Harpers Ferry, W.Va.

The Canal Towns Partnership is aimed at boosting tourism spending. A recent study showed that 4.1 million people visited the park in 2010, up from 3.7 million a year earlier.

The nearly 185-mile towpath runs from Cumberland through Georgetown in Washington. It was linked in 2007 to the Great Allegheny Passage, enabling people to walk or pedal from near Pittsburgh to the nation’s capital.

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