"Dolphin's Barn" is an area on the southwest edge of inner Dublin, named for the Dolphyn family who apparently had a barn there when it had not yet been swallowed by the metropolis. Molly was living in the area with her father when she and Bloom first met, and he remembers being with her at a party "In Luke Doyle's long ago. Dolphin's Barn, the charades." This encounter at the Doyle family house was one of their earliest meetings, and after the charades Bloom kissed her. Dolphin's Barn also figures in the Martha Clifford intrigue, because that is where she receives mail, and possibly lives.
Ithaca gives Brian Tweedy's address in Dublin as "Rehoboth, Dolphin's Barn." This might refer to several different streets in the area (Rehoboth Avenue, Rehoboth Terrace, and Rehoboth Place are all present-day addresses, and Gifford mentions a Rehoboth Road), but Molly pins it down in Penelope: "the first night ever we met when I was living in Rehoboth terrace we stood staring at one another for about 10 minutes as if we met somewhere."
That first meeting was almost certainly at Mat Dillon's house, but Bloom also thinks of Molly staring at him as he enacted Rip Van Winkle in the charades at Luke Doyle's place: "Rip van Winkle we played. Rip: tear in Henny Doyle's overcoat. Van: breadvan delivering. Winkle: cockles and periwinkles. Then I did Rip van Winkle coming back. She leaned on the sideboard watching. Moorish eyes." In Penelope Molly remembers "the night he kissed my heart at Dolphins barn I couldn't describe it simply makes you feel like nothing on earth." Ithaca observes that this consequential encounter kept Bloom up all night: "Once, in 1887, after a protracted performance of charades in the house of Luke Doyle, Kimmage, he had awaited with patience the apparition of the diurnal phenomenon, seated on a wall, his gaze turned in the direction of Mizrach, the east."
Kimmage is a separate suburb nearly a mile south of Dolphin's Barn. It is not clear why Joyce should have located Doyle in both places, though perhaps he had in mind an address located somewhere in between. In The Chronicle of Leopold and Molly Bloom, John Henry Raleigh observes that Clive Hart and Leo Knuth "say there was a real Luke Doyle, a building surveyor, who lived at Camac Place, more properly described as being in Dolphin's Barn, rather than in Kimmage" (85). The fictional couple at that address were "Luke and Caroline Doyle," whom Ithaca mentions as having given the Blooms a wedding present. "Henny Doyle," whose torn overcoat Bloom used as a charades clue, may have been one of their grown children, or perhaps Luke's brother. Molly thinks of him in Penelope as "an unlucky man" who was always "breaking or tearing something in the charades."
Both Lestrygonians and Ithaca mention Martha Clifford's address "c/o P. O. / Dolphin's barn lane," and in Sirens Bloom writes to her there. But he recognizes that she may be using a post office box to shield her actual place of residence, just as he is. Reflecting on the name "Gerty" that he heard attached to his latest fancy in Nausicaa, he subjects it to same skeptical scrutiny that he gives "Martha": "Might be false name however like my name and the address Dolphin's barn a blind."