303 Dartmouth is located on the NE corner of Dartmouth and Commonwealth, with 315 Dartmouth to the north, across Alley 424, 152 Commonwealth (287 Dartmouth) to the south, across Commonwealth, 151 Commonwealth to the east, and 306 Dartmouth to the west, across Dartmouth.
303 Dartmouth was designed by architect Robert Gould Shaw (of the firm of Shaw and Shaw) and built in 1876-1877 by David H. Jacobs & Son and Standish & Woodbury, builders, one of two contiguous houses (151 Commonwealth and 303 Dartmouth). The two houses are designed to create a symmetrical composition on the Commonwealth Avenue façade, and 303 Dartmouth is designed to achieve similar symmetry, with pavilions at either end, on the Dartmouth façade.
303 Dartmouth is located on an unevenly-shaped lot shared with 151 Commonwealth. The combined lot for the two houses is 58 feet by 124.6 feet. On Commonwealth, 303 Dartmouth’s façade is 20 feet and 151 Commonwealth’s is 38 feet. On the alley, 303 Dartmouth’s façade is 30 feet, four inches, and 303 Dartmouth’s is 27 feet. 8 inches.
303 Dartmouth was built as the home of banker Arthur Hunnewell and his wife, Jane Hubbard (Boit) Hunnewell. They previously had lived at 273 Clarendon. Arthur Hunnewell was the brother-in-law of the house’s architect, Robert Gould Shaw; he and his wife, Isabella (Hunnewell) Shaw, lived at 151 Commonwealth. Arthur Hunnewell’s brother, Hollis Hunnewell, lived at 315 Dartmouth, the house immediately to the north of 303 Dartmouth, which had been built ca. 1870.
Arthur Hunnewell is shown as the owner of 303 Dartmouth on the 1883, 1888, 1898, and 1908 Bromley maps.
Arthur and Jane Hunnewell also maintained a home in Wellesley (named in honor of his mother’s family, the Welles). Jane Hunnewell’s niece, Florence Dumaresq Boit, is credited for introducing the game of golf in New England, constructing a seven-hole course on the lawn of the Hunnewell’s estate in Wellesley in the early 1890s.
During the 1880-1881 winter season, the Hunnewells were traveling in Europe and 303 Dartmouth was the home of his brother and sister-in-law, Walter and Jane Appleton (Peele) Hunnewell. They had lived briefly at 91 Marlborough earlier in 1880; their primary residence was in Wellesley. They had moved from 303 Dartmouth by the 1881-1882 season and Arthur and Jane Hunnewell had resumed living there. By the 1882-1883 season, Walter and Jane Hunnewell were living at a new home they had built at 261 Commonwealth.
During the 1889-1890 winter season, the Arthur and Jane Hunnewell were living elsewhere and 303 Dartmouth was the home of paper manufacturer and former Congressman William Augustus Russell and his wife Frances Spofford (Hall) Russell. They had lived at 257 Commonwealth during the 1888-1889 season. They had moved by the 1890-1891 season and the Hunnewells had resumed living at 303 Dartmouth; by the 1891-1892 season, the Russells were living next door, to 151 Commonwealth.
Arthur Hunnewell died in October of 1904. The Heirs of Arthur Hunnewell are shown as the owners of 303 Dartmouth on the 1912, 1917, and 1928 Bromley maps.
In October of 1930, 303 Dartmouth was acquired by the Katharine Gibbs School. The school already owned the two houses immediately to the east, at 151 Commonwealth and 135 Commonwealth, and also owned 90 Marlborough and 92 Marlborough. In August of 1936, it acquired 21–23 Marlborough.
In August of 1931, the school applied for (and subsequently received) permission to change the occupancy of 303 Dartmouth from a private dwelling to a school and dormitory, and to change a window to a door to provide an additional basement entrance.
In August of 1935, it cut through doors between 151 Commonwealth and 303 Dartmouth, and in January of 1946, it cut through doors between 151 Commonwealth and 135 Commonwealth on the second, third, fourth, and fifth floors.
In mid-1953, Katharine Gibbs School acquired 6 Arlington to consolidate its operations in one location.
In August of 1953, 303 Dartmouth was acquired by real estate dealer Thomas J. Diab’s Baid Realty Corporation (Baid being the reverse spelling of Diab). At the same time, he also acquired 135 Commonwealth, 151 Commonwealth, 90 Marlborough, and 92 Marlborough from the school. The school retained 21-23 Marlborough, converting them from dormitories to classrooms.
In 1955, The Commonwealth School, Inc. (Charles E. Merrill, President) acquired 303 Dartmouth and 151 Commonwealth.
In January of 1956, the Board of Appeal approved the School’s plans to consolidate the buildings and to construct an addition at the rear for use as a gym and dining room (probably replacing an addition constructed in 1902 behind 151 Commonwealth).
Commonwealth School continued to be located at 303 Dartmouth and 151 Commonwealth in 2014.