The collision occurred about 10 p.m. on Route 137 at Route 45 as a 26-year-old Round Lake Beach man in a 2010 Chrysler sedan headed east on Route 137.
“The driver of the Chrysler was attempting to make a left turn onto the ramp leading to Route 45,” Lake County Sheriff Deputy Chief Chris Covelli said.
The Chrysler driver turned left, directly into the path of a 2010 Yamaha motorcycle traveling west driven by a 56-year-old McHenry man, police said.
The motorcyclist, who was wearing a helmet, was unable to avoid a collision and was thrown from the Yamaha when it struck the sedan.
He was taken to Advocate Condell Medical Center in Libertyville and is listed in critical condition with life-threatening injuries.
The Chrysler driver was not injured.
The sheriff’s office’s Technical Crash Investigations Unit is investigating the collision.