The incident happened in the Hillside Drive area of Dunloy, Co Antrim on Monday morning.
The PSNI say officers received a call shortly before 10:30 am to say a masked man armed with a handgun had entered a house through the back door and threatened the female occupant.
The woman fled to a bedroom where she barricaded herself and her daughter until officers arrived.
Invesitgating officer Detective Constable Marty McCaw said: “We are making every effort to identify the man with the gun.
“He is described as being around 5’ 7” tall and of stocky build with a local accent.
“He was wearing a black sweat top, dark or blue bottoms and a woollen mask.”
DC McCaw is appealing for anyone who witnessed anything suspicious or may have information relating to the incident to get in touch with him in the Reactive and Organised Crime branch in Coleraine on the 101 non emergency number.
Alternatively information can be passed to Crimestoppers on 0800 555 111.