good lunch in southern monmouth....
Give us a few more details - setting, food type, price, how far south, etc. and we'll be more than happy to help. There are good lunch eats to have here.
Without any of the above, given the way I feel today, I'd go to Harpoon Willy's on the River in Brielle and have some grilled clams, a burger, and a coupla IPAs.
If you meant southwestern MC, I'd suggest maybe Vietnam Bistro in Howell.
If you want pizza, Pete & Elda's, although a bit of a cliche, is fun and kinda unique, but not that far south.
Then again, there is always . . . .
Harpoon Willy's is pretty much Barnacle Bill's South - riverfront, great burgers, grill behind the bar, type thing. Only it has a much more pleasant atmosphere.
One other, quite different suggestion would be Frank's on the north end of Main Street in AP- great corned beef and pastrami.
A second would be, again completely different, to grab a few beers and eat funky pork roll sandwiches at The Committed Pig in Manasquan.