Defining a shapefile's coordinate system by selecting an existing coordinate system

Steps:

1. In ArcCatalog, click the shapefile whose coordinate system you want to define.
2. Click the File menu and click Properties.
3. Click the XY Coordinate System tab.
4. Navigate to and select the coordinate system you want to use.

   The coordinate system's parameters are listed in the Current coordinate system text box. You can double-click the coordinate system for more information.

5. Click OK on the Shapefile Properties dialog box.