MAINE

State-issued motorcycle plates began on June 1, 1905, at the same time passenger plates were first issued.  The 1905-11 first-issue motorcycle plates were slightly smaller than passenger and dealer plates and were identified by an "A" prefix.  These remained valid until December 31, 1911, unless sold or transferred.  The highest known 1905-11 motorcycle plate is #A.761.  A list of 1905-11 motorcycle plate numbers issued by calendar year appears on the Maine Prestate State page.

A new state law providing for annual registration and plates for 1912 described motorcycle plates as "a registration seal or other distinguishing mark," indicating that the state was considering issuing a disc such as those being used in Massachusetts and Vermont.  However, an undated porcelain plate was issued in 1912, which for the only time ever was full-sized like all other plates that year.  The highest known 1912 motorcycle plate is #A385.  In 1913-15, small vertical dated unpainted brass strips were issued annually, with smaller motorcycle plates resuming in 1916.