who built madison square garden

Madison Square Garden was built by different people depending on which version you mean. The most famous early one, the 1890 Madison Square Garden, was built by a syndicate that included J. P. Morgan, Andrew Carnegie, P. T. Barnum, Darius Mills, James Stillman, and W. W. Astor, with architect Stanford White designing the building. The 1925 Madison Square Garden was built under boxing promoter Tex Rickard and designed by Thomas W. Lamb.

Quick Scoop

If you mean the current Madison Square Garden in New York, it is the modern arena built much later than those historic versions. If you want, I can also tell you who designed the current one and when it was opened.