I believe Allen died in Maryland or Washington DC. He was born the same.
I do not know where Mary was born. If born in 1861, then Tallahasee Florida. She would have died in Upstate New York, if 1938. Mary salter allen split her time between her daughter in Upstate NY and her son in texas or other states. If Mary Salter Chaires was the same as Mary Salter Allen or her mother, I am not sure. if a generation above, then I do not know much. My mother referred to her Grandmother, who died in 1938, as Mary salter Chaires.
There is the possibility that may was adopted as a teenager when her parents died, and perhaps Chaires was the adoptees last name and Allen was her given name.
She may have lived in Baltimore. That side of family was from Tallahassee, but one moved from DC to NY.