Clarence Howard Clark Sr. (April 19, 1833 – 1906) was an influential banker, land owner, and developer in Philadelphia, Pennsylvania. Ten years after his death, the New York Times called him one of the city's "most prominent men of his day."
Clark was born in Providence, Rhode Island, on April 19, 1833, to Sarah Crawford Dodge and Enoch White Clark. The family moved to Boston that same year, where Enoch, a financier, incurred substantial debts. They then moved to Philadelphia in January 1837, where Enoch and his brother-in-law, Edward Dodge, founded the banking firm E. W. Clark & Co. later that year.
That firm did well, earning enough to pay off the debts in seven years, then to propel the Clarks to a place among the city's wealthiest families. The firm opened branches in New York, St. Louis, and New Orleans, and made considerable money performing domestic exchanges in the wake of the 1836 revocation of the charter of the Second Bank of the United States and the Panic of 1837. The elder Clark died in 1856 of complications of nicotine poisoning. The firm went on to control many public utility and railroad properties.
In 1854, Clarence Clark joined the family firm. The firm was dissolved on December 31, 1857, and reformed the following day with these partners: Clark, his older brother Edward White Clark, Frederick J. Kimball, and H. H. Wainwright.
Clark was instrumental in developing West Philadelphia, which was transformed over the 19th century from an area of farmland and light industry to a streetcar suburb. Clark bought land from various sellers, including Nathaniel B. Browne, a lawyer and landowner who had developed West Philly's first residential blocks in the 1850s. Among his partners in development were William S. Kimball and a man named McKlosky. At one point, he owned "the ground from 42nd to 43rd Street, Walnut to Pine".