The trail was closed west of Central Park Avenue in Logan Square while officers investigated.
A man was arrested at the western end of the 606 Trail after police responded to a report of gunfire Thursday morning in the Logan Square neighborhood.
No injuries were reported in the shooting, which happened in the vicinity of the trail, Chicago police spokeswoman Sally Bown said.
The trail was closed west of Central Park Avenue as police investigated, she said.
Video from WGN9’s helicopter showed officers arresting a man who jumped over a fence at the western end of the trail.