Check box to show Topo Map as background:

Zoom to a county by selecting from the list below

Drag the map in any direction to pan.

Hold the shift key and left mouse button to select an area to magnify.

Click on the map to open a window with links to benchmark reports for the county and 15' USGS Quadrangle in which you clicked. Close the info window by clicking on the x in the upper right corner.