These two links will show you which Sanctuaries are accredited with American Sanctuary Association and Global Federation of Animal Sanctuaries.
GFAS Accredited Sanctuary. Humane and responsible care of the animals has been confirmed by onsite visits by trained inspector(s), and the nonprofit meets the definition of a true sanctuary. In addition to meeting these requirements for verification as a true sanctuary, the facility has additionally achieved Adequate Performance or higher in each of the following areas after a thorough examination against strict criteria, as required for accreditation status: governance, finance, guidelines, education and outreach, staffing, physical facilities, security/safety, and the veterinary medical program.
GFAS Verified Sanctuary. Humane and responsible care of the animals has been confirmed by on an onsite visit by a trained inspector. In addition, the sanctuary meets the definition of a true sanctuary: the facility has nonprofit status, all required licenses and permits, does not engage in commercial trade (with some exceptions allowed such as the purchase of animals who might otherwise end up in slaughter), allows no or restricted contact with the public, only inpidual welfare-centric research is allowed, and no intentional breeding of animals occurs, with sound practices in place to prevent propagation.
Note that both Accredited and Verified Sanctuaries provide humane and responsible care of the animals, as confirmed by an onsite visit. A “verified” status as opposed to an “accredited” status often reflects constrictions imposed by financial resources.