The Fortress of Solitude is a fictional fortress appearing in American comic books published by DC Comics, commonly in association with Superman. A place of solace and occasional headquarters for Superman, the fortress is typically depicted as being in frozen tundra, away from civilization. Its predecessor, Superman's "Secret Citadel", first appeared in Superman #17, where it was said to be built into a mountain on the outskirts of Metropolis. By issue #58 (May–June 1949) it is referred to as the Fortress of Solitude, seems at a glance to be a freestanding castle, and is said to be located in a "polar waste". When the Fortress reappears in 1958 and for the first time takes center stage in a story ("The Super-Key to Fort Superman", Action Comics #241), it is again an underground complex in a mountainous cliffside. Traditionally, the Fortress of Solitude is located in the Arctic, though more recent versions of the Superman comics have placed the Fortress in other locations, including the Antarctic, the Andes, and the Amazon rainforest. The general public in Superman's world is either unaware or at best only vaguely aware of the existence of the Fortress, and its location is kept secret from all but Superman's closest friends and allies (such as Lois Lane and Batman). A trademark of the Fortress is that it contains a memorial statue of Jor-El and Lara, Superman's Kryptonian parents, holding a large globe of Krypton. Although Superman has living quarters at the Fortress, his main residence is still Clark Kent's apartment in Metropolis. The arctic Fortress of Solitude concept was first created for pulp hero Doc Savage during the 1930s.

Krypton is a fictional planet appearing in American comic books published by DC Comics. The planet is the native world of Superman and is named after the element Kryptonite. The planet was created by Jerry Siegel and Joe Shuster, and was first referred to in Action Comics #1 (June 1938). The planet made its first full appearance in Superman #1 (summer 1939). Krypton is also the native world of Supergirl, Krypto the Superdog, and Power Girl (in her case, an alternate-universe version designated "Krypton-Two"). It has been consistently described as having been destroyed shortly after Superman's flight from the planet, although the exact details of its destruction vary by time period and writers. Kryptonians were the dominant species on Krypton.

Smallville is a fictional town in comic books published by DC Comics. The childhood hometown of Superman, Smallville was first named in Superboy vol. 1 #2 (May 1949). The town is the setting of many Superboy comics where Superboy defends Smallville from various threats.