There is growing attention to community-based services for preventing adverse health care outcomes among people aging with dementia. We explored whether the availability of dementia-centered programming within older adult centers (ie, senior centers)-specifically, adult day services (ADS), social adult day centers (SADCs), memory cafes, and caregiver support-is associated with reduced hospitalization, emergency room use, and total Medicare costs for community-dwelling individuals ages 75 and older with Alzheimer's disease and related dementias (ADRD), and whether associations differ by the relative size of the local jurisdiction. We used a novel dataset that links Medicare claims data with data from an organizational census of municipally based Massachusetts older adult centers. Living in a community with an older adult center that facilitates access to ADS and/or SADCs was associated with reduced hospital utilization and costs among residents in smaller jurisdictions. We found no evidence for associations concerning memory cafes or support groups. These findings underscore the potential of older adult centers in curbing health care costs and acute care usage among individuals with ADRD, particularly in smaller communities with centers that provide access to ADS.