Ephraim Shay (July 17, 1839 – April 19, 1916) designed the first Shay locomotive and patented the type.

He was born on July 17, 1839, in Sherman Township, Huron County, Ohio. His parents were James and Phoebe (Probasco) Shay.

In 1861, he moved to Muir, Michigan, and shortly after enlisted in Company D, 8th Missouri Volunteer Infantry. From his American Civil War Diary, Ephraim wrote "Received marching orders. Quite a coincidence; on the day I am 22 years old I start on my first expedition to defend my country's honor and flag." Ephraim served in the Western Theatre of the war, under General William Tecumseh Sherman. He was honorably discharged in 1864, returned to Ohio and married Jane Henderson on July 26 of that year.

He and his wife then moved to Ionia County, Michigan, to be near other family members in Portland, Lyons, Muir, and Sebewa. In 1870 they moved to Sunfield, Michigan, where Ephraim operated a steam Sawmill. There, they had their son, Lette, on January 26, 1870.

Sometime after 1873, they moved to Haring, Michigan, where Shay established a general store and sawmill. In 1876 or 1877, Ephraim had an idea to use a locomotive to haul logs. With maple strips on pine rails, the origins of the Shay locomotive were put to use. Ephraim started working with Lima Machine Works (later Lima Locomotive Works) in Lima, Ohio, and in 1880, the first Shay Locomotive was shipped to a customer in Grand Rapids, Michigan. In 1881, Shay started filing patents. Lima built 4 Shay locomotives in 1881, and were up to 37 Shays in 1883. In 1884, Lima had a 34 page catalog, with 5 different models of Shay Locomotives. By the late 1890s, Shay Locomotives were shipped all over the world.

In 1888, Shay moved to Harbor Springs, Michigan. There, he designed and built a hexagonal shaped house with six wings opening off the central core with a tower on top, still in existence today. The walls, inside and out, were stamped steel. In 1891, Shay built an all steel boat that was 40 feet long and a beam of 6 feet, named the Aha. What's left of the Aha is now back in Harbor Springs. Shay also designed and operated a private water works for Harbor Springs.

Shay started his own railroad, the Harbor Springs Railway (nicknamed the "Hemlock Central"), which was chartered in 1902 and dissolved in 1912. Three locomotives to Shay's own design were the only motive power. The road predominantly hauled lumber, but was also used for sightseeing at 25 cents a head. Shay also made sleds with clear Maple runners as Christmas gifts for the children in town, over 400 made over the years.

In 1912, Ephraim's wife Jane died on July 24. Ephraim died on April 19, 1916.

The Harbor Springs Area Historical Society sponsors the "Shay Days" festival, on a weekend close to his birthday each year at the hexagon house. In 2005, the festival was held July 15, July 16, and July 17.