The 2021 Mid-Hudson Young Environmental Scientists (MH-YES) Program took place in-person this year from July 26 to August 13 at sites in both Millbrook, NY at Cary Institute and in Poughkeepsie, NY along the Fall Kill Creek and at a Marist College laboratory. The 2021 MH-YES program team included four scientists, two high school science teachers, two undergraduate student mentors, and eight high school students. All students, scientists, and one high school teacher hailed from Dutchess County, and one high school teacher was from neighboring Ulster County. Over the course of the three-week program, students learn to develop and complete scientific research projects related to watershed ecology. The entire group collaboratively collected data on water and soil ecology, then they divided into two groups to plan and carry out studies with these data. The two studies were: Effects of Japanese knotweed on the riparian zone of the Fall Kill and Wappinger Creek and How stream proximity and urbanization affect soil nutrients. In addition to field and lab studies, the MH-YES participants engaged in several enrichment activities, including field trips to Norrie Point Environmental Center and Innisfree Garden. The students gave two final presentations: a virtual presentation to the Fall Kill Watershed Coalition and an outdoor in-person presentation to family and friends at the Mid-Hudson Children’s Museum.