Robert S. Crain (February 12, 1865 – August 26, 1928) was a lawyer and farmer from Maryland who was active with the Democratic Party.

He served as legal counsel for the United States Brewers' Association against Prohibition for more than 20 years.

[1][3][4][5] He also represented Pennsylvania Railroad, Chesapeake and Potomac Telephone Company and United Railways of Baltimore.

[1][2][3] Crain helped secure Baltimore as the site of the 1912 Democratic National Convention.

[3] Crain advocated for state funding for a road between Baltimore and Southern Maryland.

[1][4][6] Crain served as the supervisor of elections and as a member of the excise board of Baltimore.

They had two sons and two daughters, Robert Jr., William George, Eleanor Morgan and Margaret Bennett.