At the same time the 106th Regiment was being formed in St. Lawrence County, a company of men of Irish Heritage was being organized in Potsdam by Captain James O'Connor and [then] Lt. Thomas Hickey, to join General Michael Corcoran's Irish Legion. By September 18, 1862, the Company was fully recruited and left for Camp Scott, Staten Island, to become Company A of the 164th Regiment, commanded by Colonel John E. McMahon. It was mustered into the Army of the Union on November 19, 1862, for a term of three years. Lt. Hickey was promoted to Captain, and assumed command of the Company in February, 1863.
Captain Hickey's Company totaled 86 men, including 43 from Potsdam. Fifty-nine of the soldiers were born outside of the United States, including 42 born in Ireland, 15 in Canada, one in France and one in Germany.
The occupations of the men were varied, and included on cooper, one shoemaker, four blacksmiths, one teacher, two painters, one stone cutter, two mechanics, one doctor, one stone mason, nine laborers, and 57 farmers. They ranged in age from 17 to 44. Captain Hickey himself was born in Canada, and was a mechanic.
The Regiment battles included Suffolk, Black Water, Spottsylvania, Tolopotemy, Cold Harbor, Petersburg, Strawberry Plains, Deep Bottom, Ream's Station and Boyden Road. In the battle of Cold Harbor on June 3, 1864, Captain Hickey received five wounds and his right arm was shattered. His right arm was amputated, but an abscess formed in the right shoulder which made a second operation necessary, and from this, the gallant Captain died. Captain Hickey died on July 7, 1864, age 25 years.
The Potsdam Public Museum has a number of Captain Hickey's personal items to include his sword, Bible, Pocket Watch, a Whiskey Glass and a diary which contains several entries to his wife, Joanna, during the two months preceding his death.
Both of his daughters, Mary (aka Minnie), born December 1861, and Anna, born November 1864, graduated from Potsdam Normal School and became teachers. It was Mary Hickey who presented the Hickey Collection to the Potsdam Normal School Museum in 1933.
There is also a Hickey Memorial Window depicting Christ in the House of Martha and Mary (Luke 10:38-42) at St. Mary's Church in Potsdam.