William Milnes Jr. (December 8, 1827 – August 14, 1889) was a nineteenth-century congressman and industrialist from Virginia and Pennsylvania.

Born in Yorkshire, England on December 8, 1827, Milnes immigrated to the United States with his family in 1829, settling in Pottsville, Pennsylvania.

He attended public schools as a child, and went on to learn a machinery trade.

Milnes engaged in mining and coal shipping before moving to Shenandoah, Virginia in 1865.

He was interred in the family plot in the Methodist Church Cemetery in Shenandoah.