Illinois Avenue
The names of the 3 Monopoly red properties are Indiana Avenue, Kentucky Avenue and Illinois Avenue.
The three red squares are Illinois Avenue, Kentucky Avenue and Indiana Avenue.
B&O Railroad
It was originally Purple, but it was changed to brown.
Kentucky Avenue, Indiana Avenue, and Illinois Avenue. If you want names in some localized/themed version, I refer you to the related links section.
New York, Tennessee, and Kentucky (Part of the trio) are the closest with state names.
This answer only applies to the original monopoly. The three red properties are Kentucky Avenue, Indina Avenue, and Illinois Avenue. They cost $220, $220, and $240, respectively.
In the original US version : Kentucky Avenue, Indiana Avenue, and Illinois Avenue.In the UK version : Strand, Fleet Street, and Trafalgar Square.
oriental avenue, conneticut avenue and vermont avenue are the light blue propeties in monopoly
The browns (Old Kent Road & Whitechapel Road in the UK edition) In the US version, the properties in the dark purple color group, namely: Meditteranean Avenue and Baltic Avenue.
As of September 2008, the Avenues are:Kentucky, Indiana, Illinois, Atlantic, Ventnor, Pacific, North Carolina, Pennsylvania, Mediterranean, Baltic, Oriental, Vermont, Connecticut, States, Virginia, Tennessee, New York.