1900 January 0
Assessed valuation in the city totaled $321,700,000.

1900 January 0
Annual clearings of the Pittsburgh Clearing House Association amounted to $1,615,641,592.

1900 January 0
Isaac Seder and Jacob A. Frank formed a partnership and organized a wholesale firm known as the Pittsburgh Wrapper Manufacturing Company, the forerunner of the Frank and Seder Store.

1900 January 0
The 12-story Empire Building was erected at 508 Liberty Avenue.

1900 January 0
Population: Pittsburgh, 321,616; Allegheny City, 129,896; Allegheny County, 775,058.

1900 March 0
Barney Dreyfuss began a 32-year reign as owner and president of the Pittsburgh Pirates professional baseball club.

1900 April 1
The Carnegie Company, with capitalization of $320,000,000, was formed by the merger of the H. C. Frick Coke Company and Carnegie Steel Company, Limited.

1900 July 1
Grant Boulevard (Bigelow Boulevard), a "rapid transit" road to the east, conceived in 1891 by E. M. Bigelow and cut out of the side of Bedford Hill, was opened to traffic after three years of work.

1900 November 14
At a dinner of Carnegie Institute trustees in the Schenley Hotel, Andrew Carnegie proposed an endowment of $1,000,000 for establishment of a polytechnic school on condition that the city provide a suitable site for it.

1900 December 12
At a testimonial dinner for him in New York, Charles M. Schwab, president of the Carnegie Company, made a speech that impressed one of the guests, J. P. Morgan, and led later to organization of the United States Steel Corporation, the greatest steel corporation in the world.

1901 January 0
The 18-story Arrott Building on Wood Street and the 16-story Peoples-Pittsburgh Trust Building on Fourth Avenue and Wood were completed.

1901 February 1
United States Steel was incorporated; the founding companies included Federal Steel Company, American Steel and Wire Company, National Tube, National Steel, American Tin Plate, American Steel Hopp Company, and the American Sheet Steel Company.

1901 February 17
Ethelbert Nevin, Pittsburgh composer of "Cradle Song," "A Day in Venice," "The Rosary," and other well-known songs, died.

1901 March 7
The "ripper" act, changing the city charter, became law. William J. Diehl, of the Magee-Flinn "ring," was ousted as mayor; Adam M. Brown, first president of the Allegheny County Bar Association and a judge of Common Pleas Court, was named first city recorder.

1901 March 11
Andrew Carnegie sold his steel interests to J. P. Morgan receiving value of $492,000,000 for it.