To set up the target in the configuration file, use the following syntax:

<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd" 
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> 
  <targets> 
    <target name="eventlog" xsi:type="EventLog" layout="${logger}: ${message}" 
            source="My Source" log="Application"/> 
  </targets> 
  <rules> 
    <logger name="*" minlevel="Debug" writeTo="eventlog"/> 
  </rules> 
</nlog> 

This assumes just one target and a single rule. More configuration options are described here.

To set up the log target programmatically use code like this:

using NLog; 
using NLog.Targets; 
using NLog.Win32.Targets; 
 
class Example 
{ 
    static void Main(string[] args) 
    { 
        EventLogTarget target = new EventLogTarget(); 
        target.Source = "My Source"; 
        target.Log = "Application"; 
        target.MachineName = "."; 
        target.Layout = "${logger}: ${message}"; 
 
        NLog.Config.SimpleConfigurator.ConfigureForTargetLogging(target, LogLevel.Debug); 
 
        Logger logger = LogManager.GetLogger("Example"); 
        logger.Debug("log message"); 
    } 
}