ImportanceWith the future of the Affordable Care Act and Medicaid program unclear, it is critical to examine the geographic availability of specialty mental health treatment resources that serve low-income populations across local communities.ObjectivesTo examine the geographic availability of community-based specialty mental health treatment resources and how these resources are distributed by community socioeconomic status.Design, Setting, and ParticipantsMeasures of the availability of specialty mental health treatment resources were derived using national data for 31 836 zip code tabulation areas from 2013 to 2015. Analyses examined the association between community socioeconomic status (assessed by median household income quartiles) and resource availability using logistic regressions. Models controlled for zip code tabulation area–level demographic characteristics and state indicators.Main Outcomes and MeasuresDichotomous indicators for whether a zip code tabulation area had any (1) outpatient mental health treatment facility (more than nine-tenths of which offer payment arrangements for low-income populations), (2) office-based practice of mental health specialist physician(s), (3) office-based practice of nonphysician mental health professionals (eg, therapists), and (4) mental health facility or office-based practice (ie, any community-based resource).ResultsOf the 31 836 zip code tabulation areas in the study, more than four-tenths (3382 of 7959 [42.5%]) of communities in the highest income quartile (mean income, $81 207) had any community-based mental health treatment resource vs 23.1% of communities (1841 of 7959) in the lowest income quartile (mean income, $30 534) (adjusted odds ratio, 1.74; 95% CI, 1.50-2.03). When examining the distribution of mental health professionals, 25.3% of the communities (2014 of 7959) in the highest income quartile had a mental health specialist physician practice vs 8.0% (637 of 7959) of those in the lowest income quartile (adjusted odds ratio, 3.04; 95% CI, 2.53-3.66). Similarly, 35.1% of the communities (2792 of 7959) in the highest income quartile had a nonphysician mental health professional practice vs 12.9% (1029 of 7959) of those in the lowest income quartile (adjusted odds ratio, 2.77; 95%, 2.35-3.26). In contrast, outpatient mental health treatment facilities were less likely to be located in the communities in the highest vs lowest income quartiles (12.9% [1025 of 7959] vs 16.5% [1317 of 7959]; adjusted odds ratio, 0.43; 95% CI, 0.37-0.51). More than seven-tenths of the lowest income communities with any resource (71.5% [1317 of 1841]) had an outpatient mental health treatment facility.Conclusions and RelevanceMental health treatment facilities are more likely to be located in poorer communities, whereas office-based practices of mental health professionals are more likely to be located in higher-income communities. These findings indicate that mental health treatment facilities constitute the backbone of the specialty mental health treatment infrastructure in low-income communities. Policies are needed to support and expand available resources for this critical infrastructure.