The first year of operation the Library was open 36 hours per week. The total number of volumes owned by the Library was 1,915 and the total number of items circulated for the year was 4,509.
In 1960 a bond issue was passed by Delphos residents to construct a new Library addtion of 8,300 square feet at a cost of $150,000. The first year after this addition was in operation, the Library was open for 60 hours per week. The total number of volumes owned by the Library at this time was 28,447 and the total number of items circulated was 68,501.
Over the years the Delphos Public Library has seen much growth in its services and staff members. The Library was open to the public 60 hours per week in 1998.
A new addition was begun in the summer of 2005 with a total of 3,683 square feet at a cost of approximately $430,000. An open house was held April 2, 2006 to show the new addition to the community.