427-429 Broadway (Thomas Jackson, 1871) is one of SoHo's many fine cast-iron buildings. It was built for A. J. Dittenhoefer, something of a celebrity lawyer of New York's Gilded Age--among other things, he campaigned for Abraham Lincoln and successfully defended Enrico Caruso against charges of sexual molestation.
I say a little more about this building, cast iron, and A. J. Dittenhoefer on my New York City landmarks blog, The Masterpiece Next Door.
National Register Number
SoHo Historic District: 78001883