After the decline of railroad travel and the sale of the company in 1987,[2] the portion of the line between Indianapolis and Delphi, Indiana, was abandoned.

[3][4] In Northwest Indiana, the trail is 4.4 miles (7.1 km) long, running through Lake County from Munster to Hammond.

[6][7] Northwest Indiana's portion of the Monon covers 4.4 miles (7.1 km), starting at the Pennsy Greenway near the Illinois–Indiana border in Munster, and running north to the Erie Lackawanna Trailhead in downtown Hammond.

The extension required the reconstruction of the old 1909 railroad bridge across the Little Calumet River, at a cost of approximately $1.5 million.

[11] The Monon Trail in the Indianapolis area runs northward starting from just north of downtown Indianapolis, passing through Martindale's Hillside neighborhood, the King Park, Mapleton-Fall Creek, Meridian-Kessler, Broad Ripple, and Nora neighborhoods, and then proceeding into Carmel and Westfield, Indiana, a length of 18.1 miles (29.1 km).