Peter Byron McLean was born in New York City in about 1832. He was the 2nd child of Peter Charles and Margaret (Swasey) McLean. He, his father, and his brothers were all painters, plasterers, and grainers (men who painted wood grain).

On 5 Oct 1861, Peter joined the 87th New York Infantry and became a 2Lt in Co. H - the Brooklyn Rifles. While at the Siege of Yorktown (1862), he was under constant shelling and was known to have been knocked to the ground by close shell. He (and almost his entire company) contracted Typhoid Fever and Malaria from being encamped by a bog. He was hospitalized and eventually sent home, however he was so ill and out of his mind from the fever that he was sent home with an attendant to care for him as he could become violent. He frequently had recurring episodes of malarial fevers and would leave his home and go to his father's where he would be tied to the bed to keep him from harming himself or others. Over time, he recovered and built a thriving painting business and moved to Roslyn.

Later in life, Peter once again suffered from a return of the malaria and became seriously ill. He suffered a breakdown in July 1893 and was hospitalized at Middletown Homeopathic Hospital (an insane assylum) where he eventually died.

Peter married Susan Wynn Frith 27 Aug 1856 at St. Marks in Brooklyn. According to her widow's pension file, she and Peter had 12 children together. I can currently account for 8 and presume the others were stillborn or if live births, did not survive infancy.
Their known children are:
Franklin B. McLean (1857-1925) m. Martha Wettrau
Washington (1859-1861)
Sarah R. (1861-1948) m. Wallace Thurston
Charles Wallace (1863-1867)
Peter (1864-bef 1895)
George Edward (1867-1915) m. Nettie Frith
Matthew Taylor (1869-1871)
Virginia Stuart (1881-1896)