The incident happened Friday in the 500 block of Saddlebrook Lane in Vernon Hills, officials said.
Police responded to a home at the location for a well-being check. After officers spoke with a male who was inside the home, he barricaded himself inside.
SWAT officers from both the Illinois State Police and Northern Illinois Police Alarm System were called to assist, Vernon Hills police said.
The woman's 50-year-old son was barricaded in the house for several hours before being detained by SWAT, police said.
The cause and manner of the woman's death remains under investigation.
Her son was being evaluated at a hospital. No charges have been filed, police said.
No further information was available.