Year 1840 (MDCCCXL) was a leap year starting on Wednesday (link will display the full calendar) of the Gregorian calendar and a leap year starting on Monday of the 12-day slower Julian calendar.
Year 1840 (MDCCCXL) was a leap year starting on Wednesday (link will display the full calendar) of the Gregorian calendar and a leap year starting on Monday of the 12-day slower Julian calendar.