Zively's route of the Old San Antonio cut across the southeast corner of Frio County, about 1.4 miles southwest of and parallel to Frio County Road 3857. Marker #99 was originally placed in southwestern Frio County, about 0.4 miles north of the Frio-La Salle County Line, roughly 1,000 feet southwest of Farm-to-Market Road 1582. This location is now on the FM Ranch.

The Texas Society Daughters of the American Revolution (DAR) documented this marker for their 1995-2001 OSR marker rededication project. The researcher noted that it was "1 mile NW of the La Salle County line on State Hwy 1582, then 1.02 miles NE of St. Hwy 1582." The point described is 1.3 miles north-northeast of its original location. In the DAR's photo, the marker is lying on its back in a field. The DAR's web site includes geographic coordinates for the marker, but they are incorrect; they are actually the coordinates for Marker #124 in Dimmitt County.

The location described by the DAR's directions is apparently on property belonging to the Bon Temps Ranch, which was established in 2002, since the DAR's visit. It could also possibly be on an adjacent property, the Four Corners Ranch. Both ranches are gated off from FM 1582, so it is impossible to approach within a mile of the marker's last known location. We were unable to contact the current owners of either property to ascertain exactly where the marker is, or even if they know of its existence.

Observed on April 25, 2015.