Organized by Atlanta’s High Museum of Art, “A Long Arc” runs at the Addison Gallery of American Art through July 31. The title comes from Martin Luther King Jr.’s remark that “the arc of the moral universe is long, but it bends toward justice.” The show includes some 220 photographs, making it sweeping and ample, while at the same time, thanks to the wondrous specificity the camera bestows, precise and intimate.

Intimacy and amplitude might be seen to join in a single image: RaMell Ross’s “iHome,” from 2012. A 19th-century mansion is visible on an iPhone screen. The person holding the iPhone is Black. Look closely, and you can see the traditional classical colonnade of a plantation house. Hand, phone, and image dominate the foreground. Looming out of focus in the background is the house, at once portal to and emanation from a spectral past. That’s a lot of history, a lot, packed into slightly more than 500 square inches.

“A Long Arc” follows its own, chronological arc. It begins with the antebellum period and Civil War. One reason that Northern photographers were so much more prevalent is that the Union naval blockade largely cut off shipments of photographic supplies from Europe. History is even more likely to be photographed by the victors than written by them.

Here is the first, and most extreme, instance of a running theme throughout the show: images taken by outsiders vs. images taken by native Southerners. That interplay is most evident in the section on the civil rights years, 1956-68, with photographs from both Northerners, such as Danny Lyon and Bruce Davidson, and Southerners, such as Ernest C. Withers and Charles Moore.

Some of those visitors you’d expect: Lewis Hine, Walker Evans, Dorothea Lange, Margaret Bourke-White, Robert Frank. There are even more whose presence is surprising: Edward Weston, Henri Cartier-Bresson, Irving Penn, Richard Avedon, Lee Friedlander, even Diane Arbus (one of her two pictures here is a portrait of Coretta Scott King).

The period from 1865-1930, the next section of “A Long Arc,” witnessed Reconstruction, the rise of Jim Crow, the emergence of the mythos of the Lost Cause, and promotion of “a New South.” These years were crucially important, but the elements of that importance didn’t necessarily lend themselves as well to visualization. This is another running theme: how the camera, confronted with daunting abstractions, like discrimination and inequality, sometimes can, and sometimes can’t reveal their human impact. The next section, covering 1930-45, very much shows what the camera can do in this regard. That’s chiefly through the work of such Farm Security Administration photographers as Evans and Lange.

The section devoted to 1945-1970 documents the postwar go-go years, when the South changed even more than the rest of the country did (no small feat). It overlaps with both the civil rights section and, a little bit, with the next section, 1970-96. That’s largely thanks to the careers of William Eggleston (who turns 85 in July) and the late William Christenberry.

The two were friends, and their work shares a nobly deadpan quality, ultimately derived from Evans. Yet each deployed that deadpan in very different, if also surprisingly complementary ways. Eggleston is a kind of Memphian magical realist. Christenberry was an Alabamian elegist. In one of those happy implausibilities that refresh the culture, the locus of both Christenberry’s work and RaMell Ross’s is Hale County, where Evans shot the photographs in his collaboration with James Agee, “Let Us Now Praise Famous Men.”

The final section, which covers 1996 to the present, has the amusing (because not inaccurate) title of “A New South, Again.” It draws on the High’s “Picturing the South” project. Starting in ‘96, the museum began commissioning photographers to document the region. That creative tension between inside and outside continues. Some have been Southerners: Emmet Gowin, Sally Mann. Others have not: Abelardo Morell, An-My Lê, Martin Parr. One associates Richard Misrach with the West, for example. Yet in his very large view of a swamp and pipeline — it’s 5 feet by 6 feet — Misrach makes the Louisiana bayous very much his own.

Even with so many photographs, and such a lot of ground to cover, “A Long Arc” finds room for internal grace notes. Evans’s 1936 portrait of Allie Mae Burroughs, from “Let Us Now Praise Famous Men,” hangs cater-corner to an even more striking, if nowhere near as famous, Lange portrait, from 1938, “Formerly enslaved woman, Alabama.” Evans’s “Penny Picture Display, Savannah, Georgia,” also from 1936, is by a set of family portraits by Evelyn Massengill, who helped run a traveling commercial photographic studio with relatives. Speaking of family, an Eggleston picture hangs near one taken by his cousin Maude Schuyler Clay.

So many of the most striking images here — of the Civil War, of economic conditions, of the civil rights protests — present mighty externalities, lives shared, public issues. Much of “A Long Arc” could illustrate a textbook for a civics or American history course, and that course would be well worth taking.

That means there’s all the more reason to note that no small part of the show’s richness is the allowance it makes for inwardness and mystery. “Southern Gothic,” after all, is no less a part of the region’s cultural baggage than “Lost Cause” or “New South.” Among the most memorable images here, because they’re often the most inscrutable and/or evocative, come from Mann, E.J. Bellocq, Clarence John Laughlin, and Ralph Eugene Meatyard. Mann is from Virginia, Bellocq and Laughlin from New Orleans, Meatyard from Kentucky. Yet their work transcends region, unless the South can be said to have a greater claim on the id and imagination than anywhere else (yes, that argument has been made). Alec Soth, another “Picturing the South” participant, isn’t a Southerner — though the Mississippi does pass through his native Minneapolis. Even so, Soth’s “Enchanted Forest (36), Texas” very much fits within the borders of this visual dream kingdom. The long arc bends. Sometimes it also shimmers.

A LONG ARC: Photography and the American South Since 1945

At Addison Gallery of American Art, Phillips Academy, 3 Chapel Ave., Andover, through July 31. 978-749-4015, addison.andover.edu/

Mark Feeney can be reached at mark.feeney@globe.com.