The incident happened around 3am.
Gardaí n the midlands are appealing for witnesses to a serious assault in Longford in the early hours of this morning.
A man in his late teens suffered serious head injuries in Ballymahon at about 3.20am, and was taken to Mullingar Hospital for treatment.
The investigation team are keen to speak to anyone who was around Main Street between 2 and 4 this morning.
Gardaí are particularly interested in hearing from passers by who may have camera footage from the street during that time period.
Strike Action: Picket Lines Up And Running Across Midlands Hospitals, Schools, and County Councils
€600m Farm Payment Delays A "Bombshell For Farm Families" - IFA
Emergency Services Attend Offaly Fire
Enoch Burke Facing Potential Return To Jail
Midlands 103 Reporter Travels To The Horn Of Africa To Cover Drought And Flooding Issues
Midlands TD Confident Government Supports Will Meet Farmers Needs
Offaly Councillor Demands FIx To Ongoing Water Supply Issue
Offaly Village Raises Concern Over Vandalism Incidents