The My Places feature in Google Maps allows you to create your own maps and share them with other users. In addition to standard placemarks and lines, you can also outline areas in your custom map. The shapes tool in Google Maps allows you to draw an outline around an area. After you've outlined the area, the entire outlined area is shown in a different color on your map. You can make multiple outlined areas, showing the boundaries between different geographic areas on a map.
Open the Google Maps website at Maps.Google.com in your Web browser.
Click "My Places" at the left side of the map.
Click "Create New Map" to create a new map or click the name of an existing map and click "Edit" to edit an existing map.
Click the button with the shape of a line and a down arrow on it at the top left corner of the map and select "Draw a Shape" in the menu.
Draw the outline on the map by clicking a start point, then clicking additional points to continue the outline around the area. Double-click the last point on the map to finish drawing the outline.
Right-click the shape on the map and select "Properties."
Type a name for the outlined area into the Title box.
Click the color box to open the Shape Style dialog. Use the options in this dialog to modify the shape's line color, line thickness, fill color and the opacity of the colors.
Click "OK" to save your outline settings.
Type a title for the map into the Title box in the left pane and click "Done" to save your map.