Offers unpaid internship? Source
Chuck Schumer (D-N.Y.) Yes https://www.schumer.senate.gov/students/internships
Dick Durbin (D-Ill.) Yes https://www.durbin.senate.gov/help/internships
Richard Blumenthal (D-Conn.) Yes https://www.blumenthal.senate.gov/imo/media/doc/Blumenthal%20Internship%20Application.pdf
Cory Booker (D-N.J.) Yes Confirmed via Booker's office
Sherrod Brown (D-Ohio) Limited financial assistance https://www.brown.senate.gov/services/students/dc-internships
Maria Cantwell (D-Wash.) Yes https://www.cantwell.senate.gov/services/internships
Kirsten Gillibrand (D-N.Y.) Yes https://www.gillibrand.senate.gov/services/internships/#compensation
Dianne Feinstein (D-Calif.) Yes https://www.feinstein.senate.gov/public/index.cfm/intern-program
Al Franken (D-Minn.) Yes https://www.franken.senate.gov/?p=internships
Kamala Harris (D-Calif.) Yes Confirmed via Harris's office
Mazie Hirono (D-Hawaii) Limited travel/housing assistance https://www.hirono.senate.gov/internships
Tim Kaine (D-Va.) Limited stipend Confirmed via Kaine's office
Patrick Leahy (D-Vt.) Stipends available, not guaranteed https://www.leahy.senate.gov/services/internships/
Ed Markey (D-Mass.) Yes Confirmed with Markey's office
Jeff Merkley (D-Ore.) Yes https://www.merkley.senate.gov/services/students/internships
Jack Reed (D-R.I.) Yes https://www.reed.senate.gov/services/internships
Brian Schatz (D-Hawaii) Yes. Small stipends under special circumstances. https://www.schatz.senate.gov/services/internships
Chris Van Hollen (D-Md.) Yes https://www.vanhollen.senate.gov/content/internships
Elizabeth Warren (D-Mass.) Interns may be eligible for a stipend https://www.warren.senate.gov/?p=internships
Sheldon Whitehouse (D-R.I.) Yes https://www.whitehouse.senate.gov/services/students/internships
Ron Wyden (D-Ore.) Yes https://www.wyden.senate.gov/services/internship/
Bernie Sanders (D-Mass.) Interns paid $12 an hour https://www.sanders.senate.gov/services/internships
Patty Murray (D-Wash.) Yes https://www.murray.senate.gov/public/index.cfm/internships