The reason most Federal Holidays are on Monday is because of President Nixon - in 1971 he combined Washington and Lincoln's birthdays into one holiday "President's Day" and moved it to the 3rd Monday in Feb. At the same time he moved 3 or 4 other holidays to give Federal Workers a standard 3 day weekend. My guess is that he picked Mondays because it's easier to keep the Federal buildings closed an extra day than it is to close them a day earlier. Since 1971 only Veterans Day has been moved back to it's official date of Nov 11th because Veterans protested the change. There are occasions when Federal Holidays are on Friday and that is when Christmas, New Years, Independance day or Veterans Day fall on Saturday. If they fall on Sunday they are observed on Monday.