William Baron Chapin Pearsons (December 19, 1824 – March 3, 1898), was an American politician, lawyer, judge, fire chief, soldier, and the first mayor of Holyoke, Massachusetts.

), he moved to Holyoke, Massachusetts, to open a practice and spent the entirety of his legal career operating out of that city.

[1] In the city's founding days in 1849, Pearsons was involved in local politics as a member of fourth estate, serving as the very first editorial writer for the Hampden Freeman, wherein his first editorial he described Holyoke, then known as Ireland Parish, as– "the infant giant of western Massachusetts, in the midst of a beautiful and fertile region noted far and wide for the industry of its inhabitants, its salubrious climate, and its enchanting scenery".

[2] Pearsons remained active in Holyoke's civic life even prior to becoming a public officeholder, serving as the first secretary of Mount Tom Lodge A.F.

[1] In 1864 he would resign from his senatorship for an appointed position by Abraham Lincoln to serve as an additional paymaster for the Union army.