Excello Mill was built in 1865 by an English immigrant that came to Middletown, Ohio to serve as the foreman of its first paper mill.
Located near the first lock of the Miami-Erie Canal, it was the most westerly writing paper mill in the country at the time–so the owners claimed. While it was originally named Harding, Irwin & Company, it was reorganized in 1873 as the Harding Paper Company.
A. E. Harding portrait. From Weeks p.277.
A Sanborn Fire Insurance Co. map from 1921.
After it was purchased in 1898 by the American Writing Paper Company, three years after Harding’s death, it was managed by Thomas Jones, Harding’s son in law. By 1916 it was known as the Harding-Jones Paper company. Excello Mill was put on the National Register of Historic Places in 1975. It closed in 1983 after becoming well known as a maker of custom fine writing paper.
For more on the history of the mill, check my friend’s writeup at Abandoned.