18 Exeter was designed by Snell and Gregerson, architects, and built in 1886 by Webster, Dixon & Co., builders, as the home of attorney William Sohier Dexter, a widower. He is shown as the owner on the original building permit application, dated January 16, 1886, on the final building inspection report, dated December 16, 1886, and on the 1888, 1898, and 1908 Bromley maps. He had lived at 57 Marlborough during the 1885-1886 winter season.
His four children lived with him: Elsie Dexter; George Ticknor Dexter, a real estate and mortgage broker; Philip Dexter, a lawyer; and Rose Linzee Dexter.
Philip Dexter married in April of 1895 to Edith Wood. After their marriage, they lived at 29 Massachusetts Avenue. Elsie Dexter died in September of 1905.
William Dexter died in September of 1908. After his death, George Dexter moved to 66 Beacon. Rose Linzee Dexter continued to live at 18 Exeter during the 1908-1909 winter season, but moved soon thereafter to 250 Beacon.
In January of 1909, 18 Exeter was purchased by Francis C. Welch et al, trustees. The sales was reported by the Boston Globe on January 28, 1909. F. C. Welch et al, trustees, are shown as the owners on the 1912 and 1917 Bromley maps.
By 1909, it was the home of Mrs. Henrietta Clementine (Bright) Inches. widow of cotton broker John Chester Inches, and their daughter, Natica Inches. They had lived at 441 Beacon in 1908.
Henrietta Inches traveled abroad, returning in June of 1914, after which she lived in an apartment at The Abbotsford at 186 Commonwealth.
During the 1913-1914 winter season, 18 Exeter was the home of Joseph Hall Cotton and his wife, Jane (Eaton) Cotton. They previously had lived in Brookline. Joseph Cotton was treasurer of the American Tube Company, manufacturers of brass tubing. By the 1914-1915 season, they had moved to 21 Commonwealth.
During the 1915-1916 winter season, 18 Exeter was the home of Laura (Colman) Hill, the widow of former Maine Governor John Fremont Hill, and their daughter, Katherine L. Hill. They had lived at 166 Marlborough during the previous season, and by the 1916-1917 season were living at 284 Beacon.
By the 1916-1917 winter season, 18 Exeter was the home of attorney Charles Francis Choate, Jr., and his wife, Louise (Burnett) Choate. They previously had lived at 30 West Cedar. They also maintained a summer home in Southborough. They continued to live at 18 Exeter during the 1917-1918 season, but moved thereafter, probably to their home in Southborough, where they were living in January of 1920 at the time of the US Census.
During the 1918-1919 winter season, 18 Exeter was once again the home of Henrietta Inches, who moved back there just for the season, and then moved back to her apartment at 186 Commonwealth.
By the 1918-1919 winter season, 18 Exeter was the home of Donald McKay Frost and his wife, Mary Mitchell (Ryerson) Frost. They previously had lived at 111 Beacon. Mary R. Frost is shown as the owner of 18 Exeter on the 1928 and 1938 Bromley maps. The Frosts also maintained a summer home in Dover, Massachusetts.
Donald McKay Frost was an attorney. He was a noted antiquarian and book collector specializing in the history and settlement of western America.
They continued to live at 18 Exeter until about 1937.
By 1941, 18 Exeter was the home of banker Francis Douglas Cochrane and his wife Ramelle (Frost) Cochrane, the sister of Donald McKay Frost. They had lived at 257 Commonwealth in 1940.
F. Douglas Cochrane was a banker and was a founder of the New England Oil Refining Company.
In late 1947, real estate dealer Thomas J. Diab purchased 18 Exeter from the estate of Mary Frost.
By December of 1947, 18 Exeter was owned by Michael Lilly. In that month, he filed for (and subsequently received) permission to convert the property from a single-family dwelling into ten apartments.
The property changed hands and in April of 2007 was purchased by the 18 Exeter LLC. In November of 2009, it filed for (and subsequently received) permission to convert the property from ten apartments back into a single-family dwelling.