CLARKSVILLE, Ind. – Indiana is now part of the Lewis and Clark National Historic Trail.

The National Park Service created the 37-hundred-mile trail in 1978, tracing the Corps of Discovery’s path through the then-unexplored western half of the modern-day United States, from St. Louis to Oregon. For 10 years, the agency has been studying whether to extend the trail to include the ground Lewis and Clark covered as they prepared for the journey and made their way to the Illinois-Missouri border.

Congress voted in March to extend the trail by 12-hundred miles to Pittsburgh. The expanded trail includes Indiana’s entire southern border, following the Ohio River as Lewis and Clark did in 1803 and 1804.

The expanded trail adds several points of historical interest, including Falls of the Ohio State Park in Clarksville. Wiliiam Clark stayed there for 11 days the October before the expedition began — it’s where he met Meriwether Lewis face-to-face for the first time.

Indiana Senator Todd Young was among the authors of the law, after an unsuccessful attempt to pass it last year.