- League of Women Voters of Montgomery County, Virginia Records, 1961/20011
- Lilia Gramatikova Architectural Collection, 1960/2007, bulk 1965/19811
- Lilia Sofer Skala Student Portfolio, 1915/2003, bulk 1915/19281
- Linda Kiisk Architectural Collection, 1968/20131
- Lois Davidson Gottlieb Architectural Collection, 1945/20091
- Lucy Herndon Crockett Papers, 1940/20151
- Margaret M. Sullivan Collection, 1932/20111
- Maria Aubock Architectural Collection, 1980/20061
- Maria Peeva Architectural Collection, 1978/20061
- Maria von der Weppen Architectural Collection, 1978/20011
- Marie-Louise Laleyan Architectural Collection, 1961/20071
- Martha Bil Manevich Architectural Collection, 1963/2012, bulk 1963/19651
- Mary Brown Channel Architectural Collection, 1936/2002, bulk 1936/19501
- Mary Fessler Papers, 1940/20011
- Melita Rodeck Architectural Collection, 1931/2003, bulk 1960/19901