A 25-year-old man from Northampton has been arrested on suspicion of rape.
The alleged offence happened in the early hours of Saturday, 4 April, in the Kettering Road area of Northampton.
A police spokesman said on Thursday the man had been released on police bail pending further enquiries.
It follows an appeal by officers after the alleged attack between 4am and 4.45am. The victim was spotted on CCTV meeting with a group of people in town and the alleged attack happened at a house a short time later.