Loop Around Lake Rita Blanca

The Lake Rita Blanca Park Trail is a long dirt loop around the lake.  Since the water level was low, most of the lake was dry.  It was not clear to me if this was a state or city park.  I saw a sign indicating that is is (or was) a state park, but I did not see it listed in my Texas State Parks directory.  Furthermore, there was no ranger station or entrance fee.