The extremely nutrient-rich, soils in this area are due to the volcanic activity combining with the glacier's deep churning of the soil. Between the rich soil and the long days of sunlight in the summer, the area has become world renown for it's gigantic vegetables and it's famed cannabis.
Although, The Matanuska and Susitna valleys combine to form one area. The two valleys are often thought of as being seperate, Matanuska being developed mainly for farming which isn't the case with Susitna.
Palmer, which is were the Alaska State Fair is held, is often thought of as being the official center and the Gem of the Matanuska Valley.