Howland Joseph Hamlin (July 13, 1850 – December 12, 1909) was an American lawyer and politician.
Hamlin studied law and was admitted to the Illinois State Bar in 1875.
He then practiced law in Shelbyville, Illinois and was involved in the Republican Party.
From 1901 until 1905, Hamlin served as Illinois Attorney General.
He was also the attorney for the Illinois Railroad and Warehouse Commission.