patrollable

As a noun patrol

is (military) a going of the rounds along the chain of sentinels and between the posts, by a guard, usually consisting of three or four men, to insure greater security from attacks on the outposts.

As a verb patrol

is to go the rounds along a chain of sentinels; to traverse a police district or beat.

As an adjective patrollable is

capable of being patrolled.

As adjectives the difference between patrollable and unpatrollable

is that patrollable is capable of being patrolled while unpatrollable is not patrollable; that cannot be patrolled.