SUMMER RESEARCH PROGRAMS
Science, Engineering, Mathematics, Social & Behavioral Studies, Humanities, Economic Sciences.
-Research Experience for Undergraduates (REU) sponsored by NSF - https://www.nsf.gov/crssprgm/reu/reu_search.jsp
-Summer Internship Program (SIP) sponsored by NIH - https://www.training.nih.gov/programs/sip
-Science Undergraduate Laboratory Internship (SULI) sponsored by DOE and all the United States National Laboratories - http://science.energy.gov/wdts/suli/
-NASA Summer Internship Program sponsored by NASA - https://intern.nasa.gov
-Gateway to Federal Opportunities for STEM Undergraduate Students - http://stemundergrads.science.gov
-Summer Undergraduates Research Fellowship (SURF) sponsored by various universities, you must search for SURF and the university name to see if they have that program or check the list by Ciencia PR - http://www.cienciapr.org/en/forum-topic/mega-list-summer-research-opportunities-undergrads