As of this writing, nmap is not built-in to Cygwin. Here is how to install and configure nmap so that you can call nmap seamlessly from Cygwin:
1) Download and install the “self-installer” from
You do NOT need the WinPCap services, I unchecked those options.
2) in cygwin, type
nano .bash_profile and add the line:
alias nmap="/cygdrive/c/Program\ Files\ \(x86\)/Nmap/nmap.exe"
3) close and reopen your Cygwin window
Now, when you type
nmap in Cygwin terminal you should now see the nmap help text.