He also owned more than 100 acres of land in South Portland, which he developed into a unique housing subdivision called the Sylvan Site.
[2] During the fall of 1926, Hinckley served as an attorney for lumber magnate and Republican nominee for U.S. Senate Arthur R. Gould.
Gould faced Democrat Fulton J. Redman in a special election to replace the recently deceased Bert M. Fernald.
During the campaign, opponents of Gould, including the leadership of the Ku Klux Klan in Maine, revealed that the candidate had paid a $100,000 bribe to former New Brunswick premier James Kidd Flemming fourteen years prior.
In 1921, as the demand for suburban housing spiked in the aftermath of the First World War, he began building a planned residential subdivision which he called the Sylvan Site.