A murder inquiry has been launched after 31-year-old Laura Marshall was found dead at a flat in Lurgan.
She was found in an apartment block in Victoria Street on Sunday evening.
A 36-year-old man has been arrested in connection with the death.
A post-mortem is to be carried out.
The officer leading the investigation, Detective Chief Inspector Eamonn Corrigan from Serious Crime Branch said: "Laura’s body was discovered at approximately 5.30pm yesterday, Sunday, 3 April.
"I would appeal to anyone who may have seen or had any contact with Laura over the weekend to contact Detectives at Mahon Road on 101 or alternatively information can be passed anonymously to Crimestoppers on 0800 555 111.
"I also want to hear from anyone who saw or heard any activity at Laura’s home in Victoria Street over the weekend until yesterday evening at 5.30pm.
Ulster Unionist Lurgan Councillor, Colin McCusker, has expressed his sadness at the news.
He said: "The news of this young woman's death has come as a complete shock to the Lurgan community. It is very sad that someone so young has lost her life. I would like to pass on my deepest sympathies to her family and friends.
"At this early stage in the police investigation, I would appeal for anyone with information to contact the PSNI.”
Sinn Fein councillor Catherine Seeley also urged anyone with information to contact police.
She said: "First and foremost my thoughts are with the family and friends of the deceased.
"This tragic event has sent a wave of shock throughout the community in North Lurgan and beyond.
"It is very early for any details to be released and the PSNI should be allowed space to carry out their investigations.
"I would call on anyone with any information to contact the PSNI immediately."