Judith Sisko was the daughter of Joseph Sisko, and half-sister to Benjamin Sisko. As of 2371, she lived in Portland. (DS9: "Past Tense, Part I")

In 2372, Joseph Sisko refused Judith's offer of help in his restaurant, using the excuse she had her own life "to worry about". Like her mother before her, Judith never put enough cayenne pepper in the jambalaya, which Joseph felt meant the kitchen wasn't a place for her to be in. (DS9: "Homefront")

At Patricia Graves's last requests, Daniel Radke arranged to have her belongings shipped to her cousin, Judith Sisko. (Star Trek: The Cantabrian Expeditions: "Said I Was Saved but You Never Said What From")

No dialogue established whether Judith Sisko lived in Portland, Maine, Portland, Oregon or another location named Portland.
While only referred to as "Judith" in dialogue in "Said I Was Saved, But You Never Said What From", it's inferred the Judith in question is Benjamin Sisko's sister, as Radke states her brother was a previous patient of his after Wolf 359.