Patrick Edward O'Connor was born in County Kerry, Ireland on Saint Patrick's Day 1820, and was Irish from the top of his head to the tips of his toes. He emigrated to New York with his parents at a very early age. He enlisted in the Regular Army on 28 November 1839, when he was just nineteen. Upon the breaking out of the Mexican war in that year he was mustered in as captain of Texas volunteers, in the regiment of Albert Sidney Johnston, fought at Palo Alto, Resaca de la Palma, and was severely wounded at Buena Vista. Shortly after the close of the war he immigrated to California, and there engaged in business.

In 1861 he raised a regiment of volunteers in California,, and was ordered to Utah, to prevent a revolt of the Mormons and rid the overland routes of plundering Indians. On 29 January, 1863, his force, numbering 200, after a rapid march of 140 miles, made in four nights through deep snow, in weather so cold that the feet of seventy-six soldiers were frozen, encountered 300 warriors in their fortified camp on Bear river, Washington territory.

The troops enfiladed the position, and after a fight of four hours destroyed the entire band. Col. Connor was commissioned brigadier-general, 30 March, 1863, and was long in command of the Utah district, where he effectively established the authority of the government. He received the brevet of major general at the close of the civil war, and having been appointed, on the petition of the legislatures of Colorado and Nebraska, to the district of the plains, organized an expedition of 2,000 cavalry to chastise the Sioux and Arapahoes for depredations on the Overland mail route, and in August, 1865, defeated the latter at Tongue River.

He was mustered out of the service on 30 April, 1866, General Connor was the leader in building up a Gentile community in Utah. His volunteer force numbered 16,000. Soon after he established Camp Douglas, near Salt Lake City, he founded there the " Union Vedette," which was the first daily newspaper printed in the territory.

He located the first silver mine in Utah, wrote the first mining law, introduced navigation on the Great Salt Lake, built the first silver-lead smelting-works, and founded the town of Stockton.

After the war he declined a colonelcy in the regular army in order to attend to his large mining and commercial interests in Utah.  With the troops under his command from Fort Douglas who had also mustered out of the Army, he obtained a contract from  the Union Pacific Railroad to furnish rail ties for the building of the intercontinental railroad which was completed at Promontory Summit in 1869.  The trees from which the ties were milled were harvested in the Uintah Mountains, east of Salt Lake City.