- 1 Mason, Josiah, 1795-1881
- 19 Masonic buildings
- 6 Masonic Hall
- 32 Masonic Temple
- 4 Masonry
- 1 Mason's Blacking Factory
- 1 Masquerades
- 66 Mass transit
- 51 Massachusetts
- 14 Massachusetts State Building
- 9 Massacre of the Holy Innocents
- 1 Massacres
- 2 Masses (eucharists)
- 1 Massett, Stephen C.
- 8 Master Humphrey's Clock
- 1 Master Street
- 11 Master Street
- 1 Masters
- 1 Mastodons
- 2 Masts
- 3 Matches
- 5 Maternity hospitals
- 1 Mathematical instruments
- 1 Mathematics
- 1 Mathew, Theobold 1790-1856
- 1 Mathew's Paper Mill
- 2 Mathews, Charles James, 1803-1878
- 1 Matias Lopez (Firm)
- 1 Matlack & Son Carbon Works
- 1 Matlock Bath, England
- 2 Matricolas
- 1 Matson's Mill
- 1 Matsumae, Japan
- 4 Matsuo-Ehe (Firm)
- 1 Matte's Slaughterhouse
- 1 Matthew & Moore Machine Works
- 14 Matthew, the Apostle, Saint
- 1 Matthews, C. J.
- 2 Matthias, Apostle, Saint
- 2 Mauch Chunk Creek, Pennsylvania
