The smallest building on the Fillmore Historical Museum grounds is the 1890s Bardsdale Post Office. It served as the area post office for a brief period of time until other post offices were established in Sespe and Fillmore. It continued to serve the people of the Bardsdale area until 1906 when it was combined with the Fillmore Post Office. After that it had various lives as a tool shed, chicken coop and children's playhouse before it was donated to the Museum in 1988. The Model A pickup was restored by Fillmore Union High School students and competed the 2002 History Channel Great Race from Atlanta, Georgia to Anaheim, California. It is housed in a garage built to reflect the style of the next door Hinckley House.

Prior to 1887, Royce Surdam and Thomas Bard were developing the property south of the Santa Clara River. The city plat was approved by the County Board of Supervisors and Surdam was advertising the lots for sale. The development included lots for a church, school, college, stores and, of course, a post office. Royce Surdam, the first postmaster, was appointed in May, 1887. However, by then, the Southern Pacific Railroad had laid track on the north side of the river. Surdam would come to the depot, pick up the mail sack and return to Bardsdale. Often he would have to return with mail for the few residents in Fillmore in his coat pocket.  This little building may have been built by William Dorman sometime between 1887 and 1897 and, according to Harold Dorman, his son, was located somewhere between the Bardsdale church and Owen St. It certainly was ready for business when Mr. Dorman was appointed postmaster in December 1897. According to Agnes Harris, the interior was very cozy on a winter day with heat from a wood stove and a large stovepipe. She also recalled that there was neither desk nor any cubicles. Mail was instead stacked neatly on a table and given out from there. The building remained in use until 1906 when it was discontinued. Over the years it was moved several times and served as a storage shed, wood shed, garage, and chicken coop finally ending up on the corner of Bardsdale and Sespe Avenues. In 1988, the little post office was opened to the public on the grounds of the Fillmore Historical Museum due to the efforts of Harold Dorman.

The Post Office now houses a sorting case from a local post office along with a rank of post office boxes and post boxes. On display are copies of Post Master appointment certificate for C. C. Elkins and two for Joel Schwartz, one from president Hoover and his reappointment from President Franklin Roosevelt. This was at a time when the post master position was a political appointment.

In the garage next to the Hinckley House, the Model A Pickup is kept. This was one of three built over the years by Fillmore Union High School students. It completed the History Channels "Great Race" from Atlanta to Anaheim in 2002. Also on display are various mechanics’ and carpenters’ tools as well as a photographic history of automobiles in Fillmore

Bardsdale - including story of Bardsdale Post Office, Accessed April 24th 2020. https://en.wikipedia.org/wiki/Bardsdale,_California.