- Railway Board of Adjustment No. 318
- Railway Mail Service1,884
- Railway Mail Service (Post-Office Department)20
- Railways and Canals Committee17
- Railways and Canals Committee (House)2
- Railways and Canals, Committee on3
- Ranking and Currency Committee5
- Rare Book Collection4
- Rare Books Division2
- Rare Books Division, Library of Congress1
- Rational Advisory Committee for, Aeronautics27
- Rational Defense Migration, Select Committee Investigating, House3
- Reading Room for the Blind6
- Readjustment of Service Pay Special Committee8
- Readjustment of Service Pay Special Joint Committee2
- Real Estate Bondholders' Reorganizations, Select Committee to Investigate, House14
- Reciprocity Information Committee3
- Reclamation Bureau6,308
- Reclamation Bureau, Interior Dept.4
- Reclamation Office1