Small‐sized cages of Cn are possible intermediate species for the formation of fullerene molecules in the discharge or laser vaporization reaction of graphite, but the studies on them are scattered mainly owing to their high reactivity and unavailability. Here, the coordinates of small‐sized carbon cages of Cn (n = 4‐30) are generated by our developed codes, and their stability and structural connectivity are studied using density functional theory. The interesting findings include the following: (a) Cage‐shaped isomers of Cn are favored with increasing size; (b) the ground state of cage‐shaped C4, C8, C26, and C30 are open‐shelled, and cage‐shaped D3h‐C6 is a second saddle point; (c) small‐sized cages welcome strained square(s); and (d) the most favored cages of Cn from C16 to C30 are structurally related to direct C2 insertion without the rearrangement process.