(This article is about the year 1817.) 1817 (MDCCCXVII)was a common year starting on Wednesday (dominical letter E) of the Gregorian calendar and a common year starting on Monday (dominical letter G) of the Julian calendar, the 1817th year of the Common Era (CE) and Anno Domini (AD) designations, the 817th year of the 2nd millennium, the 17th year of the 19th century, and the 8th year of the 1810s decade. As of the start of 1817, the Gregorian calendar was 12 days ahead of the Julian calendar, which remained in localized use until 1918.