The obituary from the NY Tribune, Tuesday 26 Feb 1861, page 2, reads: MCLEAN at Williamsburg on Sunday Feb 23, Washington, son of Peter B. and Susan McLean aged 3.
He was originally buried in Union Cemetery in Brooklyn. Union Cemetery closed and between 1893-1897 all the bodies were removed and relocated. One section of Cedar Grove was the relocation point, however the records identifying plots have been lost. It is unknown which plot the McLean family occupies.