John Putnam Chapin (April 21, 1810 – June 27, 1864) served as the 10th Mayor of Chicago, Illinois (1846–1847) for the Whig Party.

Chapin left his hometown to enter the mercantile business in Haverhill, New Hampshire before moving to Chicago in 1832.

[4] In Chicago he became a member of the wholesale and retail merchants firm Wadsworth, Dyer & Chapin until it was dissolved in 1843.

[4] Following the dissolution of the firm, Chapin joined the Canal Boat Transportation Company.

Since Chapin was a staunch Republican, he declined the nomination as he felt it was a mischievous move on the part of the Democrats.