St. John is an eroded lunar impact crater on the Moon's far side.

This is a heavily worn and eroded crater formation that is now little more than an uneven depression in the surface.

It is scarcely distinguishable from the surrounding terrain, except from the shadows cast by the outer rim.

The interior floor is uneven and marked by a chain of three small craterlets near the midpoint.

By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that is closest to St. John.