Officers are appealing for witnesses to a fatal collision which happened on the A417 in Birdlip last night, Wednesday 10 May.
Police were called shortly after 9pm with a report of a two vehicle collision just before the junction for Birdlip.
The collision involved a blue Mazda-2 which was travelling towards Swindon and a white Nissan Qashqai which was travelling towards the Air Balloon roundabout
Emergency services attended and a woman in her 40s and from Cirencester was pronounced deceased at the scene. Her next of kin has been informed.
A second woman, aged in her 30s and from Newent, was taken to Southmead Hospital in Bristol for treatment to serious injuries where she remains at this time.
A closure was put into place between the Air Balloon roundabout and Nettleton Bottom and remains in place at this time while investigations continue.
Officers from the Roads Policing Unit would like to hear from anyone who has not already spoken to police and has information they feel may be relevant.
Additionally they would like to hear from anyone who has dashcam footage they feel may be relevant.
Information can be provided to police online by completing the following form and quoting incident 449 of 10 May: www.gloucestershire.police.uk/tua/tell-us-about/cor/tell-us-about-existing-case-report/
National Highways are sharing updates on diversions which can be found here: https://nationalhighways.co.uk/travel-updates/travel-alerts/a417-gloucestershire-both-directions-i-collision-expect-delays/