"The summer house" at the Sartoris plantation is presumably a small, open-air building, designed to provide a cool place to sit on the hottest days (678). In this story, it furnishes Cousin Philip with a place to clean himself up before being introduced to "that beautiful girl" (678).
Bayard's narrative mentions many different rooms in the big house on the Sartoris plantation, including "the library" (667), "the kitchen" (667), "the attic" (668), the bedrooms for Rosa, Father, Melisandre, Bayard (and Ringo), "the dining-room" (670) and "the parlor" (680). The bedrooms are upstairs, and the kitchen is almost certainly semi-detached from the main building. The house has a "back gallery" (a veranda or porch, 669), which implies a front gallery as well.
At the time of this story, Vicksburg, Mississippi, was the last Confederate stronghold on the Mississippi River - "all we had left of the River," as Bayard puts it (669). After a long campaign and siege, the city surrendered to Ulysses Grant on 4 July 1863.
Virginia is mentioned twice in this Civil War story. The Confederate regiment that was raised in Yoknapatawpha is fighting "in Virginia" as part of Confederate Army of the Potomac - later the Army of Northern Virginia (667). And Granny has "sent her ear-rings and brooch to Richmond," which was the capital of the Confederacy (670); there is no obvious connection between the city and the Sartorises or the Millards, but perhaps Granny's jewelry was sent there as a material contribution to the Confederate cause.
The state of Tennessee is about 60-70 miles north of the fictional location of Yoknapatawpha County. In this story it is mentioned as the home of the Backhouse family (682, 693) as well as Nathan Bedford Forrest, and the site of fighting between the Union and Confederate forces (674).
Memphis, Tennessee - a major transportation center on the Mississippi River and the closest city to Yoknapatawpha - appears often in Faulkner's fictions. In this story, both Miss Rosa and Cousin Melisandre are originally from Memphis; Rosa's husband apparently owned a "supply house" there, and "used to trade" with Nathan Bedford Forrest, who was a Memphis slave-dealer before the War (688). During the War the city was "taken" by Union forces on 6 June 1862 after a battle between gunboats on the river (667).
When Cousin Philip refers to his grandfather's service "with Marion all through Carolina" (682), he means the guerilla campaign that militia forces led by Francis Marion waged against the British army in South Carolina during 1780-1781.
Jackson, Mississippi, named for Andrew Jackson, is the capital of Mississippi. During the Civil War the city was captured by Union forces twice, but at the time of this story was still in Confederate hands and an important manufacturing center.
King's Mountain, mentioned as part of the glorious military history of the Backhouse family, is the name of a town in North Carolina where a decisive battle was fought and won by the colonial forces during the American Revolution, on 7 October 1780.