According to a newspaper article, Plainfield's new post office was to be dedicated on Saturday, September 13. The new building was at 164 North Mill Street (near the intersection of Park Drive) and was being leased from Thomas E. Ellis and Wanda J. Ellis. The article provided some statistics about the growth of Plainfield's postal service:
- In 1948 they did $12,927.69 in business; in 1957 they did $59.686.02.
- In 1958 they have 14 employees; in 1948 they had 7 employees; in 1938 they had 4 employees.
- In 1938 there were 2 postal routes; in 1958 there are 5 postal routes.
- In 1938 there were 4 collection boxes; in 1958 there are 17 collection boxes.
- In 1948 they sold 250,067 stamps; in 1957 they sold 1,101,294 stamps.
NOTE: Today Plainfield's post office is at 700 North Carr Road (aka County Road 750 East).