Maryland Statutes
Part II - Peddler License -- in General
Section 17-910 - Display of Tag or Stamp; Harford County Peddlers

(a)    Each one horse peddler, two horse peddler, and motor vehicle peddler shall keep the metal tag or stamp issued under this subtitle attached to the vehicle so as to be clearly visible.
    (b)    A peddler in Harford County shall:
        (1)    keep with the peddler at all times the peddler license and a copy of the original written permission of the property owner required under this subtitle; and
        (2)    produce the peddler license and copy of the written permission on request.