Background: India is home to 243 million adolescents. Two million (9%) of them belong to Scheduled Tribes living in underserved, rural areas. Few studies have examined the health of tribal adolescents. We conducted a cross-sectional survey to assess the health, nutrition and wellbeing of adolescent girls in rural Jharkhand, eastern India, a state where 26% of the population is from Scheduled Tribes. We aimed to identify priorities for community interventions to serve adolescents and their families.' Methods: Between June 2016 and January 2017, interviewers visited all households in 50 purposively sampled villages of West Singhbhum district, Jharkhand. They aimed to interview all girls aged 10-19. Interviewers conducted face-to-face interviews with girls to administer a survey about physical and mental health, disability, nutrition, sexual and reproductive health, gender norms, decision-making, education and violence. Interviewers also measured girls' height, weight, and Mid-Upper Arm Circumference. Results: Interviewers collected data from 3324 (82%) of an estimated 4068 girls residing in the study area. Their mean age was 14.3 (SD 2.9). 82% were from Scheduled Tribes. 89% of younger girls aged 10-14 and 46% of older girls aged 15-19 were in school or college. Girls dropped out of school because they were required for household work (37%) or work on the family farm or business (22%). Over a third reported symptoms of anaemia in the past month, but less than a fifth had a blood test. The prevalence of thinness (<-2SD median BMI for age and sex) was 14% for younger girls and 6% for older girls. 45% of girls were stunted (<-2SD median height for age and sex). 40% reported emotional violence in the past year, 14% physical violence, and 0.7% sexual violence. 12% had problems associated with depression or anxiety. 30% aged 15-19 had heard of contraception. Among married girls and their husbands, only 10% had ever used methods to prevent or delay pregnancy. Conclusions: Our study identified several priorities to improve adolescent girls' health, nutrition and wellbeing in largely tribal areas of Jharkhand: reducing violence, early marriage and undernutrition, as well as improving mental health, knowledge about contraception and school retention.