A typographic or printer's foot contains 72 picas or 864 points. The Metric Act of 1866 established a legal ratio of 1200 : 3937 between the foot and the meter.
This is 0.0002% more than 304.8 mm, the length of the international foot established by the 1959 International Yard and Pound Agreement.
The Hawks point was established by Nelson Hawks in 1879, based on a printer's foot reduced by 0.375% from the standard foot of his time. It had a value of 0.013837 in (about 0.35146 mm). A variant was proposed to be exactly 83 picas or 996 points in 350 mm (ca. 0.351405622 mm/pt), giving it a value around 0.013848867 in.
The Johnson point was established by Lawrence Johnson in the mid-1800s based on a printer's foot 249⁄250 as large as the standard foot (11.952 inches or 0.996 foot). It thus had a value of 0.01383 inch. The 15th meeting of the Type Founders Association of the United States (ATA) approved the "Johnson pica" as its official standard in 1886, hence the alias ATA point. Following the 1959 standardization of the foot, this meant the American printer's foot was 303.5808 mm exactly and its point became 351.36 µm.
This size was approximated as exactly 1⁄72.27 of the modern inch by Donald Knuth for the default unit of his TeX computer typesetting system and is thus sometimes known as the TeX point, which is 351.45980 µm, and exactly 800⁄803 of the PostScript point (bp in TeX).
Like the French Didot point, the traditional American printer's point was largely replaced by the DTP point system.