[Faith Presses On]

The options:

Semiquincentennial.

Sestercentennial.

Quarter Millennial.

“The United States Semiquincentennial,[a] also called Sestercentennial or Quarter Millennial, will be the 250th anniversary of the 1776 United States Declaration of Independence (formally “The unanimous Declaration of the thirteen united states of America”).”

https://en.wikipedia.org/wiki/United_States_Semiquincentennial

[fightin kentuckian]

I vote for the Quarter Millennial.