Keystone Hall is New Hampshire’s premier substance use disorder treatment, prevention, and recovery support services center, offering both inpatient and outpatient services to men, women, families, and adolescents. Located in new state-of-the-art facility in Nashua, NH, Keystone Hall serves those with and without insurance, with a focus on serving those least able to afford treatment on their own. No one is turned away, regardless of ability to pay.