We originally found mention of Denoya in both the FIPS-55 and the GNIS. For more information, see the FIPS and GNIS Codes sections on our Miscellaneous Page.
From our notes, the earliest published mention we've found for Denoya was in the document titled List of Post Offices from Cameron Blevins and Richard Helbock.<3>
From that list, the Denoya post office opened in 1921.
If you're interested in how the shape of Oklahoma's counties, including Osage, have changed over time, we recommend the Atlas of Historical County Boundaries.
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When there's a risk of an area code running out of phone numbers, an 'Overlay Area Code' is created that has the same geographic boundaries as the existing area code. In this case, the 918 code has been Overlayed with the 539 area code. New phone numbers in the Denoya area will be assigned with one of these codes: 918 or 539. As a result, placing a call in the Denoya area will require 10-digit dialing (where you enter both the area code and then the phone number).
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A copy of their list with background information can be found at: