The national NCGIA conference Advancing Geographic Information Science: the Past and Next 20 Years was held 6/29-7/3, 2015 in Bar Harbor, Maine. More than 50 researchers from 25 institutions participated in the conference. The researchers exchanged their views of the GIScience research challenges in the past 20 years, leading edge research topics today, and emerging research areas for the future. The conference provided a platform for junior faculty and graduate students to present research findings, serve as session discussants, and interact with other researchers. The junior researchers formed teams to develop NSF- or NIH-like proposals. A team consisting of two graduate students from UB (Jeon-Young Kang, Shiran Zhong) and two from the University of Maine (Stacy Doore, Matt Dube) won the Best Research Proposal Award ('HAI risk assessment using sensor-based spatial-temporal network models').