A manhole is a hole for men to go in, not a near-surface utility access. Those square cut quick access holes often do have square metal covers. The manhole ope

A manhole is a hole for men to go in, not a near-surface utility access. Those square cut quick access holes often do have square metal covers. The manhole opens up into a vertical tube, often with a ladder built into the wall, big enough around for a man to descend into a subsurface structure. Hence, manhole. Manhole covers are always round because the tube they connect to is round, and that tube is round for structural reasons.