Alzheimer's Disease Prevalence Highest in South 

According to 2020 estimates, the percentage of persons age 65 and older with  Alzheimer’s Disease dementia was the highest in Mississippi (13.1%), South Carolina  (12.5%) and Louisiana (12.4%), compared with a U.S. average of 11.1%. The highest  rates occurred in Presidio County, TX (18.4%), Jefferson County, MS (18.2%), and  Emporia City/County, VA (18.1%). The estimated number of persons age 65 and older  with Alzheimer’s Disease dementia nationally totaled 6.4 million.