The Fields Institute, located in Toronto, Canada, is among the top international research institutes in the mathematical sciences. Its programs cover a broad spectrum of areas in pure and applied mathematics and statistics, as well as many related areas of computer sciences, physics, and theoretical biological sciences. The Institute provides a venue that facilitates interactions and communication among researchers. Its programs serve to train and inspire early career scientists and promote collaborations between university-based researchers and scientists working in industry, on topics that touch many aspects of mathematics, the physical and biological sciences, and society. The international reputation of the Fields Institute, the high level of its participants, and the broad scientific range of its programs provide numerous opportunities for researchers to pursue their own work, to learn about and to contribute to scientific advances, and to train advanced graduate students.<br/><br/>Approximately 4000 researchers from around the world participate in Fields Institute programs each year. On average 620 are U.S.-based researchers, about half of whom are offered support by the Institute. Also about one half of these U.S.-based researchers are junior faculty, postdoctoral researchers, or graduate students. Their time spent at the Institute as participants and speakers in conferences, workshops, advanced courses, and other events provides the opportunity for them to work with and learn from some of the top international researchers in their areas of specialization. This NSF grant award provides resources to support some of these U.S.-based researchers for their participation at the Fields Institute. The impact of this funding will be to provide travel and local support for approximately 92 US-based participants per year, for the most part early career mathematicians, including junior faculty, students, and postdoctoral fellows.