Women are less likely to choose STEM educational programs, hold STEM degrees, or enter the STEM labor force. Several factors contribute to this including intrinsic psychological factors, external environmental variables, academic mindsets, and STEM attitudes. This paper discusses a 10-day long STEM camp aimed at engaging high school girls in authentic field-based environmental research. The goal of the camp is to foster and encourage interest in STEM fields through hands-on laboratory experiences, discussions with female scientists, field trips, and a broad range of research-focused authentic scientific activities. The descriptive research study used observational qualitative and quantitative data to better understand and improve the future of informal STEM experiences for high school-aged girls. Results of the study found that girls were more likely to see themselves in STEM fields; exposure to authentic scientific research, hands-on fieldwork, and final research presentations promoted self-efficacy and confidence in their ability to undertake university-level research. Finally, the camp provided a place to engage with other females through academic and social collaboration.