>> The Mississippi delta is in Louisiana. <<
Part of it, yes. The other parts are in Mississippi and Arkansas.
And the southern most portion of Missouri's "boot heel", consisting of 6 counties, adjoining Arkansas, part of the Mississippi River's alluvial plain. Until the early 1900s, a swamp. Once drained it became some of the most fertile farm land in the country.
Those 6 counties produce 30% of all Missouri's agriculture products.