Authorities say the fight took place in the parking lot of Shellhammer's Bar in Christiana shortly after 2 Sunday morning.
Reports indicate the 22 year-old victim and her boyfriend got into an argument with the suspect after the bar had closed.
Police say the suspect the struck woman, cutting her head and fracturing an orbital bone. The victim was treated at Christiana Hospital.
Anyone with information on the assault is asked to contact the state police.
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