=IF(ISNUMBER(SEARCH( ---- Trying to search multiple options to return the same value

I'm trying to reclassify certain clients by the state they are located in. We want all IL, MO, AR, TN clients to be "Central" region clients.
Currently the formula I am using, which is working the way intended, is


M2 is ", IL", but I want it to also include the other states listed above as other options. How can I also include ", MO" ", AR" ", TN" to this formula so that those states will also return the "Central" value using only one formula?

slightly different method that I think will work

Ok so I assume you have all your central region codes in column M i.e. M2 = IL, M3 = MO etc. If this is the case highlight all of the central regions in column M and in the name box (should display the cell name like M2) type Central and hit return.

This has named this group of cells as central. Now if you enter the following formula in place of the one above you will get the same result but for all regions that are in the "central" named cells.