The short answer is that Putnam City was planned, promoted, and named, but never became an incorporated city. Israel Mercer Putnam, a lawyer and real-estate developer, imagined a new township northwest of Oklahoma City in the early 1900s.
Putnam and his partners promoted the area around what is now NW 39th Expressway and State. The interurban railway stop was called Putnam City, and Putnam also offered nearby land for a proposed state capitol complex.
The capitol proposal failed, and incorporation papers for Putnam City were never filed. The school district name endured because four one-room schools consolidated under the Putnam City name in 1914.
The museum's early-history research adds important nuance: court records and later research indicate the school district ultimately obtained legal ownership of its first school site through prescription or adverse possession rather than a simple donated-land story.
That is why Putnam City remains a school district identity, a source of pride, and a place in memory, even though there is no separate Putnam City town government.