I'm unaware on any contemprary account of their uniforms. It would appear that the two companies of San Patricios, as officially formed in 1847, were to wear the standard National Guard Uniforms of a high collared, dark blue/ red plastron coatee with light blue trousers. There is a modern painting of a San Patricio private on page 126 of Brassey's book on the Mexican-American War. On page 131, the writer opines that after the Battle of Churubusco, they wore fatigue grey frocks or white canvas jackets.
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