The 72nd Pennsylvania Infantry Regiment, also known as Baker's Fire Zouaves, was a Union Army regiment from Philadelphia, Pennsylvania which was active from August 1861 to 24 June 1864 during the American Civil War. The regiment was recruited by Colonel Edward Dickinson Baker from among the firemen of Philadephia, and it was originally known as the 3rd California Infantry Regiment, as its ranks included a number of Californians intent on taking part in the war. After Baker's death at the Battle of Ball's Bluff, the regiment was reclaimed by Pennsylvania, and it was attached to the Army of the Potomac and saw its first action at the Battle of Seven Pines. Nearly half of the regiment was lost in the West Woods at the Battle of Antietam, and it defended "the Angle" at the Battle of Gettysburg, participated in the Overland Campaign, and fought in the Siege of Petersburg before being mustered out in mid-1864.