Importance Although the recent proliferation of telemental health care has transformed the delivery of outpatient mental health care for many individuals in the US, little is known about how outpatients are distributed across telehealth, hybrid, and in-person care. Objective To characterize the national distribution of sociodemographic and clinical outpatient mental health groups across telehealth, hybrid, and in-person mental health care. Design, Setting, and Participants This was a cross-sectional analysis of all telehealth, hybrid, and all in-person mental health care by adults (aged ≥18 years) in the 2021-2022 Medical Expenditure Panel Survey (n = 4720). Data were analyzed from January to August 2025. Main Outcomes and Measures Average annual percentages of adult mental health outpatients who used all telemental health care, hybrid, and all in-person mental health care were calculated overall and stratified by sociodemographic and clinical characteristics. Differences in percentages using each modality were evaluated by sociodemographic and clinical strata adjusted for age, sex, and distress level (Kessler-6 scale). Exposures Type of mental health treatment used (telemental health, hybrid, or in-person). Results The analysis involved 4720 participants (2235 aged 18-44 years; 3007 female). Approximate one-fourth (27.8%; 95% CI, 25.7-29.8) of mental health outpatients received all telemental health care, 21.5% (95% CI, 19.8-23.1) received hybrid care, and 50.6% (95% CI, 48.2-53.1) received all in-person care. The percentage of patients receiving all telemental health care was higher for younger (aged 18-44 years; 31.7%; 95% CI, 29.0-34.3) than middle age (aged 45-64 years; 24.2%; 95% CI, 21.1-27.4) or older (aged ≥65 years; 19.4%; 95% CI, 16.1-22.7) adults, high school (23.1% 95% CI, 20.4-25.8) and college (34.5%; 95% CI, 31.5-37.5) graduates than those without a high school diploma (19.9%; 95% CI, 13.7-26.1), patients with incomes &gt;400% federal poverty level (33.8%; 95% CI, 30.9-36.7) than lower (range, 20.6% to 23.7%), private (30.8%; 95% CI, 28.5-33.1) than public (20.2%; 95% CI, 17.4-23.0) insurance, and urban (29.2%; 95% CI, 27.0-31.3) than rural (14.0%; 95% CI, 8.6-19.3) residence. Compared to patients receiving medication alone (15.4%; 95% CI, 12.5-18.3), those receiving psychotherapy with (25.9%; 95% CI, 23.2-28.6) or without (41.6%; 95% CI, 38.0-45.2) medication were more likely to use all telemental health. Patients with less than moderate distress (29.2%; 95% CI, 26.1-32.3) were also more likely than those with serious distress (21.2%; 95% CI, 16.7-25.6) to use all telemental health. In adjusted analyses, patients treated by mental health counselors (10.9%; 95% CI, 7.0-14.7) or social workers (8.4%; 95% CI, 4.1-12.7) were also more likely to receive all telemental health than were patients treated by other mental health clinicians. Conclusions and Relevance The findings of this cross-sectional study indicate that telehealth has become a common means of receiving outpatient mental health care in the US, especially for resourced patients with less serious psychological distress who receive psychotherapy from mental health specialists.