How To: Create point features using lat/long coordinates in Degree Decimal Minute format in a map that is in projected coordinates
ArcMap uses 'project on-the-fly' functionality to line data up that has been assigned a coordinate system and geographic coordinates are stored in the units of decimal degrees.
Given a table that has coordinate values in standard latitude/longitude (Degrees Decimal Minute) format, there is no direct way to add this data to a projected map.
Instructions provided describe the process of manually adding points in degrees decimal minutes to an empty feature class that is in a projected coordinate system using the standard editing tools.
The procedure to add data in degrees minutes and seconds (dms) coordinates is slightly different and can be found in the articles listed in the Related Information section at the bottom of this article.
Create a new feature class in a projected coordinate system.
Add the empty feature class to the map document.
On the Editor toolbar, click 'Editor > Start Editing'.
Set the Task to 'Create New Feature'.
Set the Target to the empty feature class.
Click the Sketch tool on the Editor toolbar.
Right-click in the map and select 'Absolute XY'.
Enter the X or longitude coordinate in the format D MM.DDW ddm (82 13.641W ddm).
Enter the Y or latitude coordinate in the format D MM.DDN (41 24.686N).
Go to the link 'Web Help: Creating point features and vertices' and review the section entitled 'Creating a point at an exact x,y location (Absolute X,Y)'.