James W. Loewen, professor emeritus of sociolology at the University of Vermont, writes in Southern Cultures:
"Sundown towns are (or were) all white by design. To determine whether a community is or was a sundown town, considering racial composition is paramount. Towns with no African Americans on their census rolls pass this first test, of course, but so do towns with non-household blacks. Izard County, Arkansas, for example, had 191 black residents in 2000, but only two African American households; the rest were inmates of the state prison. Live-in servants in white households also do not violate the taboo against independent black residents.
A town or county with very few African American households decade after decade, or with a sharp drop in African American populations between two censuses, is a sundown town if their absence is intentional. Credible sources must confirm that whites expelled African Americans, or took steps to keep them from moving in. Such local sources as county histories, WPA files, and even centennial coffee-table books may acknowledge that a community drove out its African American population or took steps to ensure that none ever entered. More often, though, residents do not write such things down, but conversation can be revealing. Credible details about what happened, gathered from more than one person, confirm a town's sundown status. Newspaper articles, tax records, or the 'manuscript census' can corroborate oral histories."
The term "sundown town" developed because many of these towns marked their city limits with signs indicating that blacks were unwelcome after sunset.
In his book Sundown Towns: A Hidden Dimension of American Racism, (available in print and ebook formats) Loewen points to several possible and confirmed sundown towns in our state including: Okemah, Henryetta, Marlow, Cleveland, Paden, Stilwel, and Norman. In Norman, a 1949 University of Oklahoma Board of Regents ruling broke the "effective but unwritten law that no Negroes remain in the university city of Norman after dark" (Tulsa Tribune 1949-09-15). Julius Ceasor Hill, a 40-year-old African-American graduate student from Tulsa, had protested to OU President George L. Cross that his reservation for a room on the south base campus had been canceled. The University's Board of Regents met and ruled that Ceasor was entitled to housing accomodations on the campus. Cross was then ordered "to enforce segregation 'to the greatest extent' but empowered him to 'set up temporary housing for Negroes."