The Yrgin, an Ohlone tribelet, controlled the San Lorenzo Creek watershed on the east side of San Francisco Bay. Yrgin territory included the present day cities of Hayward and Castro Valley and extended from the bayshore to the heights of Walpert Ridge. Walpert Ridge gives every indication of being a religious/ceremonial center. Rock walls, rectangles, prayer circles, and other features are scattered across Walpert’s “high country.” We have no clue as to what, if anything, went on there, but we do know that Walpert Ridge possesses extensive views that encompass much of the central and south Bay Area. This is a place, like Mt. Diablo, where one can have the sense of being on top of the world, looking out over creation.
Some of the sites on Walpert Ridge are owned by the East Bay Regional Park District but held in “land bank” status. Others are on land held by private owners. One should secure permission before visiting any of them.
Randall Milliken suggests in A Time of Little Choice that the Yrgin and the Jalquin may have been the same people. He does not represent this possibility on his tribelet maps in Native American History Studies for the Los Vaqueros Project: A Synthesis, which we follow here.