Day freed his slave woman, Eliza, in 1846, declaring in the manumission document that he lived "under a Republican Government & believing as I most sincerely do that all the Human Race without respect to sex or Coulour (sic) should & ought to be free.
His home on Sunshine Avenue in Fork, Maryland near Mount Vista Estates and the intersection of Harford Road was the site of an incident on July 11, 1864.
When the advance guard for Harry Gilmor's raiders was in the area, Ishmael Day placed a large Union flag over his gate.
Gilmor's Ordnance Sergeant Eugene Fields told Day to take the flag down.
The State Convention of Maryland, formed to construct a new constitution, formally ordered that Day be thanked for his actions.