The outer wall of Barrow has been heavily eroded by subsequent impacts, and reshaped by intruding craters.

As a result, the rim now resembles a ring of rounded hills and peaks surrounding the flat interior.

The interior of Barrow has been resurfaced by lava flows, leaving a flat surface that is marked by many tiny craterlets.

Faint traces of ray material from Anaxagoras to the west forms streaks across the floor of Barrow.

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