Where is Oracle sqlplus located?

You can locate the sqlplus executable in Windows by running in a CMD shell

dir /s /b c:\sqlplus.exe

Suppose you find the file at

c:\oracle\product\11.2.0\client_1\bin\sqlplus.exe

Then you have determined that your ORACLE_HOME is:

c:\oracle\product\11.2.0\client_1

Assuming the above ORACLE_HOME, set your environment variables (Control Panel > System > Environment Variables). Below is example, so modify these to match the ORACLE_HOME you determined above.

ORACLE_HOME=c:\oracle\product\11.2.0\client_1

TNS_ADMIN=c:\oracle\product\11.2.0\client_1\network\admin

PATH=  *(add this below the end of your PATH)*
         ;c:\oracle\product\11.2.0\client_1\bin

If you are running Oracle Server on your local computer you can also find it by right clicking the running Oracle process:

In my case it is in

C:\app\TZNind\virtual\product\12.2.0\dbhome_2\bin

Usually in $ORACLE_HOME/bin and usually they suggest to run

. oraenv

to prepare your environment.