American Society of Civil Engineers Los Angeles Section San Luis Obispo Branch Historic Civil Engineering Landmarks (L) = Local HCEL        (R) = Region 9 HCEL        (N) = National HCEL San Luis Obispo Branch Landmarks Map San Luis Obispo Branch Website Los Angeles Section Landmarks Map Los Angeles Section Landmarks List Region 9 National Historic Civil Engineering Landmarks List Los Angeles Section Website No. Landmark Name Location Coordinates 47 Southern Pacific Railroad - San Luis Obispo to Santa Marguerita (L) San Luis Obispo County Lat: 35.3290 N Lon: -120.6908 W 58 Salinas River Dam (L) San Luis Obispo County Lat: 35.3372 N Lon: -120.5027 W