The 36 star flag became official on July 4th, 1865 and was in common use during the time of the assassination of Abraham Lincoln in April of that year. That flag was only official for two years and was replaced by the 37 star flag in 1867 with the admission of Nebraska. The 38-star flag became official on July 4th, 1877 with the addition of Colorado. The 38 star flag was in use for 13 years and not replaced until 1890. Flag makers, hoping to get a jump on production, began making 39 star flags in the fall of 1889 in anticipation of the addition of Dakota as the next state. They were disappointed as Congress divided Dakota into North and South and also admitted Montana,Washington and Idaho the same year so the state count jumped to 43. So the 39, 40, 41 and 42 star flags never legally existed.
Tomorrow, US Military Flags Rita Bay