James O'Hara (c. 1752 – 1819) was an American military officer, businessman, and captain of early industry in Pittsburgh, Pennsylvania, United States.

He was born in County Mayo, Kingdom of Ireland, the son of Major John O'Hara, and in 1765 attended the Jesuit College of Saint-Sulpice in Paris.

He served in the Coldstream Guards, a regiment of the British Army, in 1770, and resigned his ensign's commission the next year to gain business skills as a clerk in a ship broker's office in Liverpool.

He did business during the next decade as a government contractor, providing Generals Josiah Harmar and Arthur St. Clair with provisions during the Northwest Indian Wars.

He set up a salt business, a sawmill, and with partner John Reed established Pittsburgh Point Brewery[citation needed].

[2] The attack transport ship, USS James O'Hara (APA-90) saw extensive action in World War II.

In 1963 the novelist Agnes Sligh Turnbull published a fictionalized account of his life entitled The King's Orchard.