A number of roads were cordoned off after the woman was struck by a van whilst crossing Clifford Street near B&M at around 11.19am.
Road closures remain in place at Church Street, Clifford Street, Chapel Street and St Georges Street, whilst police establish how the collision happened.
You can see footage of the police scene in our video player above, as well as further footage here.
The woman suffered serious injuries and was taken to Royal Preston Hospital by ambulance.
An ambulance spokesman said: "I can confirm that we were called to an RTC on Chapel Street involving a vehicle and pedestrian at 11.19am this morning.
"An ambulance and advanced paramedic in a rapid response vehicle attended.
"The ambulance then conveyed a female patient to Royal Preston Hospital."
A police spokesman added: "We were called to Clifford Street, Chorley, at 11.22am today (February 16) to reports of a road traffic collision involving a van and a pedestrian.
"The female pedestrian has suffered serious injuries. Emergency services remain at the scene and a road closure is in place.
"Anyone with information can call police on 101, quoting log 462 of February 16, 2022."
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