An alert by the Modoc National Forest says that entering or being in the Wild Horse Holding Facility Closure Area is prohibited from July 9 to August 3.
The map shows a development in S35 T43N R11E but does not identify it.
The ArcGIS Viewer puts it on Airport Road which may correspond to County Road 74, the address given in a Google search.
The order did not indicate if the closure was related to the Montgomery Pass roundup.

► Get the truth about wild horses and the wild horse advocates at westernhorsewatchers.com.
