The Chicago River and Michigan Avenue Bridge were reopened just after 1 p.m. after being shut down Monday for about an hour for a "suspicious item" found near the bridge.
The item was described as an unattended bottle in a plastic bag spotted under the bridge.
The river's waters were closed to boats and the bridge was shut down to pedestrians, Police News Affairs said. Cars were still being allowed to cross the bridge.
A bomb squad was called to the scene just before noon as well as several firefighters and police officers.
Officers were seen removing police tape and allowing pedestrians back on the bridge at about 1:10 p.m. and the News Affairs said the area was clear. It's not yet known what was in the bottle.