Charles Adams Platt, the son of John Henry Platt and Mary Elizabeth Cheney Platt, was born in 1861 in Manhattan. Although best remembered today for his landscape and country house designs, he was also nationally known for his etchings, landscape paintings, commercial architecture, and institutional projects. He was largely self-taught in each of these disciplines, building his success on his ability to reconceive the classical tradition in architecture for the needs of his wealthy, powerful clients. Born into a wealthy family with several artist relatives, Platt developed an early interest in art by enrolling in classes at the National Academy of Design in 1878 and joining the Art Students League in 1879. Vacationing in upstate New York that year, he met the painter and printmaker Stephen Parrish, who encouraged Platt to investigate the newly revived art of etching. Platt quickly became adept in the medium, earning the nickname "the boy etcher" and becoming a successful member of the etching revival by 1881. To advance his growing interest with painting, Platt traveled to Europe from 1882-1886. He studied in the atelier of Jules Joseph Lefebvre in Paris from 1884-1885 but often worked independently within a circle of friends including Henry Oliver Walker, Kenyon Cox, and Dennis Miller Bunker. Platt met Annie Corbin Hoe in Europe and they married in the spring of 1886. Both of their fathers died that summer, and Annie died in childbirth in early 1887. Platt recovered slowly, returning to his work in earnest in the summer of 1889 when living at the Cornish Arts Colony, where he had been invited by Walker. Founded by sculptor Augustus Saint-Gaudens in 1885, Cornish provided Platt with a vibrant community of artists, writers, and intellectuals, including the landscape architect Ellen Biddle Shipman and sculptors Herbert Adams and Paul Manship, as well as the land on which Platt designed and built himself a residence and garden in 1890. The following year, Platt received a commission for a house and garden from his Cornish neighbor, Annie Lazarus. Platt sought initial assistance from friend Stanford White and designed for Lazarus a residence patterned after an Italian villa and sited to frame views of Mount Ascutney. Platt further explored his ideas on villa architecture during his 1892 trip with his brother, William Platt, to photograph Renaissance gardens in Italy, the results of which he published in Italian Gardens in 1894. After returning from Italy, Platt received house and garden commissions from several neighbors in Cornish, many of whom would remain lifelong patrons. Thanks to positive attention in the architectural press and the ties of his family and friends to influential patrons, Platt began to attract commissions beyond Cornish, first for gardens and then for entire country estates. Platt was published in Guy Lowell's AMERICAN GARDENS in 1902, in which his classically influenced garden designs were printed alongside those of Wilson Eyre and McKim, Mead & White and in contrast to the naturalistic designs favored by Frederick Law Olmsted. Herbert Croly, editor of ARCHITECTURAL RECORD and a friend of Platt, published a positive review of Platt's work in 1904. By 1913, Platt's substantial body of work was published in the MONOGRAPH OF THE WORK OF CHARLES A. PLATT by the Architectural Book Publishing Company. Platt continued to design country houses throughout his career, but he devoted much of his time to important urban and institutional commissions after 1920. Many of these commissions came from the Vincent Astor estate office, which employed Platt from 1906 through 1932, and from residential clients with institutional interests. For the Astor estate, most of Platt's work consisted of converting Manhattan tenements to more luxurious middle- and upper-class apartment dwellings. Previous patron Charles Lang Freer commissioned Platt to design the Freer Gallery of Art in Washington DC in 1913, the first of Platt's nine museum commissions. Platt also completed or consulted on several large-scale campus planning projects, most notably for the University of Illinois at Urbana-Champaign and for Phillips Academy in Andover, Massachusetts. Throughout his life, Platt maintained his house and garden in Cornish, New Hampshire, and an office and residence in Manhattan. With his second wife, Eleanor Hardy Bunker, whom Platt married in 1893, Platt had five children. Among the children were William (1897-1984) and Geoffrey (1905-1985), who followed in their father's footsteps and practiced architecture in New York City; the Department of Drawings & Archives also holds the William & Geoffrey Platt archive. Charles Platt died in Cornish in 1933.

This collection contains materials related to Platt's personal and professional lives, the bulk originating from Platt's office in the form of project drawings, photographs, and records documenting architectural projects from 1901-1933. Several earlier projects and projects completed by Platt's office after his death are also documented. A small group of drawings was created for publication only, and some drawings may have served as both project records and presentation drawings. The archive also contains typescript transcriptions of correspondence from Platt's travels to Europe in 1879 and from 1882-1886, as well as transcribed letters to his wife, Eleanor Hardy Bunker Platt, and a diary kept during his brief engagement as a member of the Food Administration in Italy after World War I. Additional papers include limited personal and professional correspondence. Lastly, the collection contains original glass plate negatives of photographs of Italian Renaissance gardens taken by Platt and/or his brother William Platt in the spring of 1892. Platt incorporated some of these images in ITALIAN GARDENS, published by Harper in 1894.