1829 (MDCCCXXIX) was a common year starting on Thursday of the Gregorian calendar and a common year starting on Tuesday of the Julian calendar, the 1829th year of the Common Era (CE) and Anno Domini (AD) designations, the 829th year of the 2nd millennium, the 29th year of the 19th century, and the 10th and last year of the 1820s decade. As of the start of 1829, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1923.