Abstract: A well casing security device and method. The security device includes a cover including a sidewall, a top, one or more stabilizers, and a means for attaching the cover to a well casing or to its concrete slab to render it vandal-resistant. A locking support ring is provided for attachment to either the well casing or to the concrete slab surrounding the casing. The locking support ring includes a ring body with a plurality of braces. Each of the braces includes an arm defining a slot between the arm and the ring body. The cover includes a plurality of brackets enabling rotational engagement cover with the locking support ring. Locking means are provided on the cover to lock the cover to the locking support ring. The locking means includes a key operated lock that is tamper resistant and insures that the well casing cannot be accessed easily by an intruder.